Muerte súbita infantil/ SUDDEN UNEXPECTED INFANT DEATH.

SUDDEN UNEXPECTED INFANT DEATH.

Coghill Research Laboratories
Excellence in bioelectromagnetics

EXTRA LOW FREQUENCY (ELF) ELECTROMAGNETIC FIELDS AND SUDDEN UNEXPECTED INFANT DEATH.
Roger Coghill MA, Coghill Research Laboratories, January 1993
""

We have now finally released this worrisome study, begun in the mid 1980s, since sufficient time has passed for the parents of the dead infants to have overcome their grief (for the most part). The UK Foundation for Sudden Infant Deaths (a largely Government funded charity) has never given us any assistance in our attempts to conduct a larger study, refuses to fund any investigations by our laboratory (see comments regarding Prof. Jean Golding below), and still gives no advice to parents concerning avoidance of high ELF electric fields. Surrey University (also largely Government funded) has suppressed this study by refusing to have it included in my PhD submission. Prof Golding has recently become a co-author in a study from Bristol University to be presented at the BEMS meeting in Los Angeles 1999, some six years after our results were presented at a BEMS meeting.

Note: subsidiary tables charts and diagrams will be added later.
We believe that research into this area, together with the statisitics, has been manipulated by successive UK Governments, against the public interest.

SUMMARY
A case referent study of all SIDS cases in Inner North London occurring between January 1986 and July 1988 suggests that there is a statistically significant dose-response relationship between SIDS and proximity to ELF EM fields from external sources such as electric railway lines. 46 percent of the cases were found to be within an average of 50 metres of clearly identifiable EM sources. Moreover there was an unexpected but consistent fall in the average age at death with increasing proximity to different EM source types. The relation appeared to be strongly linear when tested by Pearson’s coefficient (r= .983) and other critical ratios (z= 5.3). No such strong correlation appeared when distance from subterranean water streams and conduits were considered, though the study was flawed by difficulties in obtaining data on such sources.

Attempts to raise funding for a measured case-control study proved unsuccessful, but all but one of nine sporadic spot and period measurements indicated that ELF electric or magnetic fields were without exception above the limits for ELF exposure recommended by SWEDAC for adult computer operators (i.e 25V/m and 250 nT). A larger study would throw light on the possibility that a further large proportion of SIDS cases are related to chronic ELF exposures from domestic appliances.

The original table by Coghill constructed to show a correlation between SIDS and ELF EM fields:

General Introduction
With the increased quality of neonatal medical expertise has come a consistent fall in the number of infant deaths. A century ago 150 out of every 1000 infants in England would die before the end of their first year of life. By the 1980s only 10 would die out of each 1000, and of these 6 do so in the first six months, partly due to low birth weight or congenital heart disease. There are implications from the Henhouse project (Berman, Chacon et al., 1990) that prenatal exposure to ELF EM fields is related to embryo malformation, that some animal studies (e.g. Persinger, 1974, S 204; Pafkova, 1980) suggest that mammalian offspring exposed to ELF EM fields in utero tend to be of low birth weight, and epidemiological evidence points towards a reproductive risk from chronic VDU exposure (e.g Goldhaber, Polen et al., 1988)

These controversies lie outside the scope of this thesis. What is relevant is that in industrialised countries there remains a stubborn if small number of infants (about 2 in every 1000 live births) which die suddenly and unexpectedly from no apparent disease or other cause. These infants are now classified to Sudden Infant Death Syndrome (SIDS) and constitute about one third of post neonatal infant deaths. The major symptoms, if that is the right word for the small miscellany of observations from such cases, are listed in Table...

The infants are for the most part well nourished, of normal weight, and apart from a slight indication of cold or snuffles, a degree of irritability and an altered cry, exhibit no obvious ill health before their sudden demise. SIDS is now, because other causes have been slowly diminished by medical care, the major cause of post neonatal death in industrialised countries. As with childhood leukaemia and chronic fatigue syndrome, no aetiology has ever been identified, though there have been many hypotheses of causation (one source, Knight, 1983, suggests over sixty) including allergy to milk, overheating, viral infection and position during sleep.

Early research
Suggestions that electromagnetic energy may be implicated in SIDS was first proposed by Gustav von Pohl in 1929. His book Earth Currents (p.81) claimed "The most dangerous places to sleep and stay during the day must be in an intensely radiated nursery". However he only chronicled one case, that of a 16 month old child, hence of an age which would not qualify under the present SIDS definition, and he only referred to geomagnetic anomalies. Another non-peer-reviewed 1976 report by Bachler, a professional dowser, claimed in its English edition (1989, p 82) when discussing adverse health effects from subterranean aquifers that "babies and young children instinctively flee from radiated areas. I also mentioned that babies and small children, who are incapable of avoiding those areas by themselves, might suffer severe damage if they are confined to their cribs, despite their cries and screams of protest".

Bachler claimed to have collected 1500 cases on infants and small children, and included 15 cases in her book. However only four of these were infants and two were over 12 months old. She carried out no controlled studies. One other study, from Aarrhus University Geology Institute (Metcalf Gad, Boie, xxxx), reported that 14 out of 18 SIDS events occurred above geological anomalies. Only one study (Eckert, 1976) has claimed that SIDS deaths were over-represented near sources of electromagnetic energy, both man-made and artificial. This study too was uncontrolled, derived from work carried out by third parties (Hildebrand, 1967, Valdes-Dapena, 1968), and has not been given much credence by the medical community. Golding (1985) referred to it as follows:

"There is a curious study analysing information from Hamburg, West Germany, and Philadelphia, Pennsylvania which indicates that the risk to infants living in the basement or ground floor is higher than other levels. He incidentally purports to show that the regional variation of sudden infant death in the two areas is a function of uncommon magnetic fields and stray electric currents. No other study has been carried out to assess the validity of these findings - but is important to point out that in countries with AC current such as Britain any electromagnetic fields are of minimal strength".

A closer reading of Eckert’s study however, reveals that his principal (not incidental, as Golding says) claim is that "possible causal relationship exists between electromagnetic fields and SIDS cases".

Eckert recommends that the hypothesis "be checked by on-site measurements, animal experiments, and by more research on magnetic fields as a stressor for infants". His findings report that "the nearest surroundings of the dwellings of 200 cases were examined to find out if electric and/or magnetic abnormalities existed". He found that often the dwelling is situated within a triangle of about 100 metres side bounded by two electric railways and two tramlines ; also within a rectangle 200 by 100 metres bounded by three electric railways and a tramline;. within a triangle of about 300 metres incorporating three electric railways, also very near to one of the many lines.

Eckert kindly sent to this author a map locating some 65 of the Philadelphia cases (fig. xxx). of which all but 11 were near what appeared to be tram or railway lines, and there appeared also to be a cluster of 17 cases (26%) inside a triangle occupying less than 10 percent of the map area. However, no other data was provided, and Eckert’s argument was not fully supported by the information he supplied (e.g. there was no evidence provided of high water table effects, or from underground streams or sewers). Eckert’s study also reported that "a similar string of 18 cases in a street length of 3.2 kilometres had also been observed. This street where it seems that under the earth a main water pipe was running (at the end of the street it found a water reservoir) is being crossed underground by an electric railway of several lines... 14 [SIDS] death cases have been registered within the curve of an electrical railway with several lines, very near the main railway station..."

Eckert summarised the SIDS high risk areas as follows:
1 near electric railways and their stops
2. between electric railways and water
3. between railways of various systems (i.e. rail and tram)
4. at the final points of railways
5. near magnetised water reservoirs (the meaning of this was not elaborated)
6. within curves of electric rail lines (causing shortest route for earth return currents)
7. near wireless transmitters, airports, high voltage currents, churches with lightning conductors
8. moraines with "constant slack water wetness", i.e. a high groundwater table.

His comments on high rise apartment incidence arose from his separate analysis of Hamburg SIDS data for the years 1961-67, where he found that basements and ground floors were over-represented (RR: 1.32) after allowing for a higher incidence of families with more than one child in these home types. About 30 percent of the cases he examined (79 out of 261) were multiple cases at one location (e.g. three cases in one short street near undefined "high power currents"). Eckert made no field measurements, but cited Persinger (1974) and Presman (1970) as reporting a high level of inflammations of the upper respiratory tract and otitis media in rats exposed to magnetic fields, and compared these with a 1960 study by Coe and Hartmann which found the same symptoms in SIDS cases.

Moreover rats exposed to SHF fields were reported by Presman to have abnormally high calcium concentrations in their urine. (Chipperfield and Chipperfield, 1979 reported significant excesses of calcium in SIDS heart muscle, though only 7 cases were examined). He also cited a 1961 study by Maresch which suggested an electromagnetic effect on infant heart muscles in SIDS cases. Eckert concluded that both man-made and naturally-occurring electromagnetic fields were causally related to SIDS.While his study was of fairly low quality, it is surprising that no further research has ever been conducted into the hypothesis. The first study in this section reports an attempt to replicate Eckert’s findings, this time with control addresses derived from the same Coroner’s office (Inner North London).

SIDS AND PROXIMITY TO EM FIELD SOURCES:

A CASE/REFERENT STUDY

INTRODUCTION
This study attempts to replicate the findings of Eckert (1976). It covered the geographical area of Inner North London, defined as the contiguous Boroughs of Camden, Islington, Hackney and Tower Hamlets (population as at 1986: 691,200, which is 1.15 percent of the UK total), and covered 67 SIDS cases identified from the Inner North London Coroner’s records of deaths during a thirty month period between January 1986 and July 1988. There were some 11,000 live births annually during this period, so that SIDS incidence was 2.5 per 1000 live births, which compares well with national norms.

METHODS AND MATERIALS
Case data were collected by inspection of the Public Register of Deaths. Because some SIDS deaths occurred in hospitals within the area, the home address did not always originate within the geographical study area: eight cases originated outside the Boroughs. These were excluded since some were very distant (e.g. Norfolk, Glamorgan, Essex, etc.) Several cases for similar reasons ascribed to one of the Boroughs actually originated in another of them, but these were included, because inter-borough boundaries were, for the purpose of the study, ignored. Records prior to January 1986 had been archived and were not accessible. Two files of the original 79 SIDS cases thus identified were missing. Two more were excluded because the cause of death was not clearly and solely attributable to SIDS (one may have been the result of a fall, and the other reported congenital anomalies). Deducting the eight extra-borough homes left a total of 67 reference cases.

Selection of Controls
Selection of fully matched controls from the same Register of Deaths was not possible because SIDS now represents by far the largest cause of postneonatal mortality. Control infants who had died from causes other than congenital heart disease or illness were not numerous. To this small group therefore were added young people who had died from non-illness related causes (e.g. road traffic accidents, murders, fatal falls, burnings, etc.) and in this way a total of 64 control addresses was derived from the Register of Deaths within the same period of time as the cases. The oldest of these was 30 years. Suicides and congenital birth defects or heart condition related deaths were excluded from controls because other studies had identified a possible link between these events and EM fields (eg Perry 1981).

The 64 control addresses comprised all those available for inclusion, and there was no further selection when deaths from illness or suicide (including drug overdose) were excluded.. Their numbers by year are shown in Table One.

Identification of EM field sources
It was not possible to identify all sources of electromagnetic fields at ELF frequencies, nor could account be taken of non-ELF radiations. The main classes of EM fields were therefore taken to be, as shown in Table Two. Two complexities arose in that a) three cases had lived above the gravel terraces of North Islington, and b) nearby some case and control homes there were several EM sources. This was so in 18 of the SIDS cases and in 16 of the controls, (though distances were greater from the control homes). In these only the nearest source was used, except where in 4 SIDS cases (0 controls) there were several equidistant major EM sources, and these were segregated into a separate category.

RESULTS
The nearest EM source to case and control homes is shown in Table Two: The mean distance of the 35 of 67 case homes from these identified EM sources was 49.51 metres (SD23.68 ), which compared with 276.08 metres (SD 258.20) from the 64 control addresses. To see if any dose-response effects could be determined cases were subdivided into the two major divisions above and age at death in months was compared with distance from the EM source. The results are presented in Tables Three and Four. When the 35 SIDS cases were compared using distance as a simple measure of dose and age of death as a measure of response, no correlation was obvious (see Graph One).

However when the probability that different EM source types produced dissimilar field strengths was taken into account and the data was evaluated with cases grouped for type of exposure, there appeared to be a dose-response relationship when the 31 cases near artificial EM sources (46 percent of the total SIDS cases for the period) were considered. The most appropriate statistical test for this possibility is not easy to ascertain, since the dose response relationship may not be linear (magnetic fields from powerlines may attenuate with the square of the distance whereas fields from largely unbalanced EM sources may attenuate with the simple reciprocal). On the assumption that there might nevertheless be a linear component, a Pearson’s coefficient of correlation was applied, which produced an unusually high correlation coefficient of r=+.986 (i.e a very high linear correlation). No such correlation emerged from a comparative study of the (more distant) aquifer-related EM sources (Table Five).

DISCUSSION
The almost perfect linear correlation between SIDS age of death and distance from artificial EM source in the 31 cases where artificial EM sources were (on average) less than 50 metres distant appears too good to be true. As Colton (1974) remarked: ""Correlations from 0 to .25 indicate little or no relationship, those from .25 to .50 indicate a fair degree of relationship, those of .50 to .75 a moderate to good relationship, and those above .75 a very good to excellent relationship... Sometimes one encounters correlations of .95 or higher. When such correlations arise, particularly in the biological field, and where human data are involved, one should immediately be suspect.

Correlations this high are almost too good to be true. In practice, when correlation this high occurs, it is usually evident long before the plotting of the scatter diagram or the calculation of r. When unanticipated extremely high correlations are found it is wise to query whether the strong relationship might be an artifact. In this case the author had no control either over the distance from the defined EM source nor over the age of SIDS case death: both were completely independently collected variables, and the data may be regarded as valid. One could argue that these only accounted for 46 percent of the total cases in the area during the period reviewed, and that omitting the more distant cases avoids answering the question of why these other cases occurred.

However, the ubiquitous nature of EM domestic sources within any home makes it a natural possibility that some SIDS cases, perhaps as many as half, might originate from chronic exposure to ambient EM fields from domestic appliances such as storage or other heaters, electric blankets and the like which are switched on for long periods. Accordingly a possible correlation between SIDS and domestic EM field strength should also be investigated. There are indications, both in the literature and from case series, that this may be so. Ramanathan and Chandra (1988) reported that out of 34 SIDS cases no less than six had been lying on or under electric blankets or electrically heated water beds.

Another reported a SIDS case where the victim had been in a carry cot on a floor heated by underfloor electric heating. A recent Tasmanian study reported that in 69 percent of SIDS cases home heating had been operating at the time. Only 1 percent of Tasmanian homes have central heating and the probability is that the SIDS homes were being heated electrically. Though the princpipal aim of the study was to investigate position, the authors identified heating as being associated independently with SIDS. This was also the case in a Bristol University study (Wigfield et al, 1992) which did not however identify which kind of heating had been involved. It is hard to escape the conclusion that there is a strong association between chronic exposure to ELF electromagnetic fields and SIDS.

Though no equivalent correlation was found between SIDS and natural sources of EM fields from sewer or aquifer flow, as some have suggested, this may owe more to the difficulty of confirming the proximity of such sources than to the absence of any effect. The claims of Eckert are supported by the data collected in this study. One difficulty in studying SIDS causality is the difficulty in obtaining matched controls. This is because SIDS cases are the major remaining source of post-neonatal death in industrialised countries, and in this case it is not possible to use other death types such as congenital heart disease lest they also originate from EM field exposure. In this study the problem was lessened in that the addresses rather than the controls themselves were sought, and the question of the validity of these addresses, and whether they constitute a sample truly representative of the general population.

One might argue, for example, that persons killed in road traffic accidents do not live so near to congested areas well served by underground or rail transport. The RTA victims however lived no further distant from EM sources than those dying from other causes. Cases were significantly nearer to artificial EM sources than controls, and this supports Eckert’s claim. What was not expected, however, was that there was a clear dose-response relationship between distance from artificial EM sources and age of SIDS death which could not have arisen though selection or other bias, since all cases were included, and the period of selection was the maximum available.

The major symptoms of SIDS have been described above. None of these are inconsistent with an aetiology from EM exposure, and are discussed in this context below.

Seasonality
The pattern of SIDS in the Northern hemisphere is well confirmed in a number of studies, and is depicted (Knight,1983) below (Graph Three).This graph compares remarkably well with seasonal variation in magnetic field strength in a typical domestic environment (Renew, Male, 1990) (Graph Four):

Near miss SIDS
This phenomenon is where the parent notices by chance that the infant is unwell (and often cyanosing), and picks up it up, removing it from the distress location, usually to the nearest hospital or doctor’s surgery. The infant rapidly recovers and quickly becomes well again, so that in some cases the investigating doctor cannot find any sign of ill health. Sadly a second occurrence after the infant has returned to its habitual environment, is usually not so fortunate in outcome. @PARAHEAD = Position De Jongh reported that 88 percent of SIDS infants are found dead in a prone position, suggesting that this may be due to an agonal response. Other common symptoms are that the infant utters distress cries for some days before death, is often irritable, and will not settle, or refuses a feed. Some infants are found in positions very different from that in which they are placed at bedtime.

All these can be understood in the context of the infant’s sensitivity to EM fields, possibly because the cerebral myelination process is not complete in human beings until one year of life, and responds by attempting to evade the EM field region. It was suggested by Ponsonby and subsequently by Fleming that placing the infant in a supine position would by itself lessen the risk of SIDS occurrence. However recent national UK publicity to promote the advice to place the baby in a supine position for sleep has always been accompanied by advice not to overheat the infant ( FSIDS pamphlet, 1992).

This may have reduced SIDS cases (by upto 46 percent) for the latter rather than the former reason. In regions (e.g Gwent) where the EM hypothesis has been promoted SIDS cases have fallen by 77 percent (Table Six).

Immunological disorder
Some studies have noted disorders of immune competence reporting altered levels of IgG or IgE, though this is not confirmed in other studies. Snuffles, colds, and other infections are commonly reported during the last week of life before a SIDS occurrence, suggesting a mild immune incompetence. Laboratory studies have confirmed that even short term exposure to ELF EM fields inhibits lymphocyte cytotoxicity by upto 40 percent. Other studies (Wertheimer & Leeper, 1979; Feychting and Ahlbom, 1992) have confirmed that increased incidence of childhood leukaemia incidence is associated with proximity to important sources of EM fields. If such fields have serious adverse health effects on children it would be consistent to suggest that infants are even more badly affected. The peak age of death in SIDs is 12.6 weeks, the time when fetal haemoglobin is being replaced by the infant’s own haemoglobin, and assuming independent immunological status from the mother.

Prematurity and Low birth weight
This common SIDS feature may of course predispose any infant to ill health effects. However experiments on chick embryos and live animals have found that in utero exposure to EM fields results in low birth weight and prematurity or even spontaneous abortion. The last of these has been sufficiently associated with seasonal use of electric blankets generating unbalanced magnetic fields, to encourage the FDA to patent a balanced EM field electric blanket. @PARAHEAD = Overheating Overheating, long a major hypothesis of SIDS causation, has been found to be associated in many studies, but no study to date has classified the types of heating used where SIDS has occurred. It would be consistent with EM field insult that electric heating is found in a noticeable proportion of SIDS cases.

Low socio-economic group
An elevated incidence of SIDS has been noted in poorer housing conditions. It would be consistent with an EM aetiology if such homes were found to be less adequately electrically wired, earthed and suffering from high humidity. Such homes are also likely to be situated nearer to electric pylons, railways and other unattractive installations. In the sample examined, for example, 9 homes (13 percent) were on average less than 33 metres from electricity substations or power lines, which is an over-representation.

Anoxia, hypoxia, and apnoea
The microbiology of oxygen transport fits well with an EM aetiology for SIDS. Infant erythrocytes are in general actually larger than those of the adult. Well replicated studies have shown that the morphology of erythrocytes (e.g echinocytic-stomatocytic transformation and blood paramagnetism) are ultimately dependent on the extramembrane electric potential difference (Glaser, 1992). Changing this potential reversibly changes the normal discocyte into an echynocyte or stomatocyte. In this event the erythrocyte (c. 5 microm. in diameter) cannot pass down the capillaries (c. 3-4 microm. in diameter) thus inducing inevitable cyanotic effects. One defensive response might be sleep apnoea, which is observed quite frequently in SIDS cases. Passive smoking is also thought to be an important SIDS risk factor. Some studies imply that the inhalation of positively-charged free radical particles may be a delivery vehicle for EM field insult (MacLaughlan, 1992).

Twins and clustering in time and place
One study found that twins were at as high as fivefold risk of SIDS if a sibling was already a victim. Others have noted clusters both in time and place. All these would fit with an EM field aetiology with an important proportion of EM sources from external locations. Notwithstanding the general plausibility of an EM source hypothesis against the background of the major symptoms listed above, and the support given to Eckert’s claims by this study, there is clearly a need to take actual electric and magnetic field measurements in sufficient SIDS case locations at death to test it against established normal field strength values. A case series of this kind has been begun and is reported next in this thesis. Until this is completed the data presented here must only be regarded as supportive. A suitable location for such a study might be the special care bay units used widely in hospitals for premature or delicate neonates. Such units are often placed very near to the electric cables supplying monitoring equipment or electric heating units in the incubators themselves.

MEASUREMENT OF EM FIELDS IN SIDS HOMES

SUMMARY
Because of the delicacy of the situation and the need to avoid intrusion on personal grief it has proved extremely difficult to make EM field measurements in newly arising SIDS locations. Not surprisingly SIDS funding and research agencies are not very willing to assist in investigating a new and unproven hypothesis among so many alternative scenarios and existing research programmes. Nevertheless, measurements of EM fields over a 24 hour period in two SIDS cot locations, and spot measurements in eight others confirm that ELF EM fields in all these locations (between 20 and 110V/m and 230-400nT)) were significantly higher than established normal levels (5-8 V/m and 60nT). A further controlled study is still needed to confirm the results of this case series.

METHODS AND MATERIALS
The 24 hour measurements were taken either with the instruments described elsewhere (Philips 1992), or with Squirrel dataloggers attached to Mersmann Fielmeters. The spot measurements were made with Mersmann Kombitest Feldmeters.

Case One: Male died Hastings, 31 January 1989, age five month These 24 hour case-control measurements were carried out in February 1990 on behalf of Hastings Borough Council Dept of Environmental Health (Sussex, England) using a Squirrel datalogger to which were attached the output leads from the Mersmann Kombitest which had been modified by Squirrel engineers. Excerpts from the report to the Hastings EHD is given below.

This infant was born prematurely and of low birth weight, but was a normal 11lbs at time of death. He had a temperature of 104C a few days prior to decease. He died the day after being moved from his parents’ room into another bedroom heated by radiant electric fire in the same apartment block, which was within 100 metres of a 275kV line. The ELF EM fields measured in that room on 8/9 February 1990, showed average electric field levels about 25V/m. (Diag. Two). A healthy control’s house equally distant from the line but much nearer the pylon itself (fields are minimal actually under pylons) was measured simultaneously and showed electric fields of only 2-3 V/m, which compares well with average levels found in the studies above (Diag. Three).

Thus the case was chronically exposed to EM ELF fields some five times the norm.

Case Two Male, died Aberdeen 26 December 1990, age six months. This was carried out in February 1992 on behalf of Camphill Architects Ltd. who carry out architectural services at the village near Aberdeen, Scotland, following a cot death near the adjacent 32kV powerline. Excerpts from the report to CAL is given below. This infant was born healthy and full term, with five elder siblings, in a village near Aberdeen. The family house was situated near to a 132kV powerline, with the bedroom in which the infant normally slept some 45 metres from the line. The ELF EM fields as measured in that bedroom on 8th February 1992 (around 40nT, and 3 V/m) were not significantly different from means measured/calculated in several recent studies of residential EM fields at ELF frequencies (Mader, Barrow et al.,1990; Renew, Male et al, 1990; Barnes and Wachtel, 1989; Agnew & Donnelly, 1991). The case house was centrally-heated by an oil-fired system, supplemented by a wood burning stove in the lounge, and there were no electric heating appliances in use.

Spot measurements
The oil fired system became defective towards Christmas, and to keep him warm, the mother placed him for most of the time in the lounge at the nearest end of the house to the overhead line, the route centre of which was approximately 24 metres distant (see Map One). From that time the infant became irritable, and restless, and did not settle easily in the new location. He died unexpectedly on 26 December 1990, and a verdict of sudden infant death (SIDS) was recorded.

Field measurements made at floor level in the lounge on 8/9 February 1992 showed that the rms magnetic field vector from three orthogonal components often exceeded 200nT (2mG), and ranged between 170nT and 270 nT (1.7 and 2.7mG) (Diag. One), which is some four times the norm (in the chart the components are disaggregated, so appear slightly lower).

Both cases are examples from some 20 consecutive cases of SIDS whose pre-thanatal EM environment was measured by this author, which all showed abnormally high EM ELF fields, though not always from powerline proximity, since appliances (e.g electric blankets, immersion heaters, storage heaters) were also implicated.

A study of 34 SIDS cases in Holland found that six were associated with electric blankets and electrically heated water beds (Ramanathan Chandra, et al., 1988) and another report implicated electric underfloor heating (Gray & Green, 1988). There is also evidence that infants placed in such fields attempt to evade them by altered cry, irritability (Golding 1985), and crawling motions: 88 percent of SIDS cases in one study were found prone, and its authors suggest this was possibly an agonal crawling position (de Jonge, Engelberts et al. 1989). Finally the incidence of SIDS in Avon dropped noticeably after heavy local media publicity suggesting that SIDS and ELF EM fields were causally linked (Bristol Journal April 7th, 1989).

Comparison of two studies (Renew, Male, 1990; Knight, 1983) establishes that SIDS events in the Northern hemisphere follow closely the seasonal pattern of residential magnetic field strengths (see Diags. Four and Five). A recent study of some 432 U.S. residences by Barnes and Wachtel (1989) found that average residential electric fields were between about 8.7 and 11.5 Volts per metre. The study by Renew, Male et al (1990) found average residential magnetic fields were about 40-60 nT (0.4-0.6mG). These mean levels were confirmed by Mader Barrow et al. 1990. Thus both the above cases were being chronically exposed to ELF fields well over four times normal residential field levels.

a) At Bristol
This was carried on behalf of Cot Death Research of Weston super Mare (Avon, England) in April 1989, and witnessed by a newspaper reported from the Bristol Journal 7 April 1989. It showed a reading of 70V/m in the cot location, into which the infant had been placed after six weeks. Previously the infant had occupied a cot next to the parents’ bed. No magnetic field measurement was recorded. The readings were carried out at night, and no indication of any nearby HVTLs were evident.

The Bristol Journal report of a 1989 survey carried out in Bristol by Coghill more than a decade ago:

Note: As a result of its findings in this study our laboratory developed the famous Coghill FieldMouse, which can warn of above average domestic ELF electric and magnetic fields. During the next decade thousands were sold, and the FieldMouse is now used in all industrialised countries (see products section of this website).

b) At Leicester
This measurement was carried out at a terrace house in Syston, Leics, on behalf of Mirror Group Newspapers. The home had recently been modified by removing a central wall and supporting the upper floor with a steel joist. The house wiring ran along the joist.The field in the bedroom was normal, but the fields under the steel joist where the mother would daily place the infants (there were two SIDS cases , twins Sian and Jade, in the family which included a third child, Liam) registered 100V/m. This illustrates the need to enquire exactly where the infant was placed for the most of the time.

c) At Rohnerts Park, San Francisco
This investigation into a cluster of SIDS ("crib") deaths was also carried out on behalf of Mirror Group Newspapers, in March 1989. In the district of Rohnerts Park (pop. 30000) in Sonoma County (pop. 370,000), 45 miles north of San Francisco, there had been three outbreaks: in November/December 1987 (10 cases in 8 weeks), in December1987/ January 1988 (34 cases in two weeks) July 1988 (3 cases in three days). A further cluster of 11 cases occurred in the same area between 9 November 1988 through December 1988. within a seven mile radius of Rohnerts Park.

Incidence of SIDS cases on the US west coast is higher than the national average, but this latest cluster received national publicity. The geographical region of Northern California has one of the highest EM traffic profiles in the world, and is also a region of disturbed geomagnetic anomaly, of which frequent earthquakes are a concomitant feature. Radio frequency traffic is now so dense that allocating frequencies to new radio stations is difficult. In addition a new cell net telephone serrvice was brought into operation in January 1989, prior to which it was under test at the time of the cluster. On Sonoma mountain (2500 ft, 35 miles distant) is a major transmitting complex of microwave and RF transmitters.

This investigation inspected the sleeping place of two of these cases (of the rest one was consideoresdi too sensitive for visit, one spoke no English, one was a drug addict, four had moved home, and two were unavailable). A further three SIDS cases from a previous clsuter were also investigated. Individual results are summarised below.

1. Nicholas M. (died 19 November 1988 age 23 months) The house is of one story wooden construction situated at Penngrove, next to a 21kV electric cable junction which developed a 70 V/m field at 20 feet. At the cribside the wall next to the crib fields were upto 50 V/m., thoguh other walls in the room did not exceed 20V/m nor did other rooms in the house..

2. Cassandra B. (died 15 April 1988, age not ascertained) The one storey house is of brick and wood constructionand well appointed. the habitaully slept along an interior wall which gave field steength readings of 50-80 V/m due to a wiring configuration in the wall which illuminated the parents’ walk=-in clothes cupboard on the other side of the wall. No other high field densities were found in the infant’s room.

3. Amber F. (died 23 June 1987 age 3 months) The house is of wood and stucco construction at Petaluma. The crib was situated in an alcove corner of a room. The mother noted that the infant consistently "skooted" (crawled) to the crib foot. The electric field density graduated from 35 V/m at the head down to 10V/m at the crib foot, due to the presence of a water immersion heater in the cupboard also in the alcove.

4. Jordan V. (died 28 November 1988, age 12 weeks) The house is a two storey stucco and wood construction at Petaluma. No electric fields above 30 V/m were noted in the infant’s bedroom. The parents advised that the child had been of normal delivery and in good health. They took a vacatiuon(lake Tahoe) but the weather became unusually vcold and to keep the infant warm in the hired ;log cabin they left it at night in front of a radiant electric fire. After five days the baby became ill and they returned home, but the infant died the night of their return. During the lasyt five days it had been restless with crying and disturbed sleep.

5. Kyle E. (died 19 November 1988, age six weeks) The home was a poorly constructed and furnished wood and plasterboard shack at Cotati. The infant slept by an outside wall at the top of which the main power cables to this house and those of several neighbours passed. A meter was at the corner some 20 metres away. Electric fields thorughout the house were unusually high, but attentuated down the wall where the infant slept in a metal crib to about 30 V/m. This investigation was terminated when the newspaper had collected this preliminary data, and no opportunuity was available for a more thorough investigation.

d) At Pontypridd Glamorgan
Christopher B. ( died 14|August 1992, age 4 months) These were requested by Glyntaff Neighbourhood Community Trust and by the solicitor for the mother, whose second child was being kept in care because it was failing to gain weight at the home. (There was a possibility of legal proceedings by the mother to regain her child from care). These measurements was taken over only a 4 hour period during the day of 29 September 1992. No abnormal levels were observed ( mean electric field 3.3V/m, mean magnetic field 55nT), but a subsequent search at the Register of Deaths revealed that four SIDS events had taken place in the same road or adjacent within the last six years, and within 100 metres.

A 132kV powerline runs through the estate some 80 metres distant, but it was claimed by the South Wales Electricity Board that this line had not been in use for two years. Measurements below the line at the same time as the home measurements confirmed that it was not certainly energised during the time of the measurements. Note: In order to carry out a more balanced study data on some 60 cases in Mid Glamorgan have been now been collected from the Register of Deaths, incident during the six years to 1992. No ethical committee approvals have yet been obtained to carry out this survey.

DISCUSSION
Though these few preliminary measured observations support the possibility that EM fields are implicated in SIDS, selection bias is obvious in the two 24 hour measurements, and in the 4 hour measurements. The Rhonert Park cluster had also received wide publicity and had been linked by the media to a new microwave transmission system brought into service on a nearby mountainside. They are not therefore of any use for a proper scientific assessment. In response to press and Parliamentary pressure following this author’s findings in Inner London a prospective study was begun in Avon in August 1989 using instruments supplied by NRPB. It was an add-on to an existing study being carried out by a team including Jean Golding and Peter Fleming, funded by partly by FSIDS but did noit actually receive additional funding. This study is still in progress but it has not been revealed whether electric and magnetic field strengths are being collected, or any other details.

The authors did report however on 34 SIDS caes with respect to position and heating in February 1992. In setting up a properly designed retrospective study it is essential to choose a population area of some density in order to obtain sufficiently large a sample. This in turn may introduce other confounding factors (e.g. traffic fumes). In a rural area like mid-Glamorgan though some 60 cases were identified these occurred over a six years period, many of the original families had since moved home, partly as a result of their tragedy.

CONCLUSIONS
There is evidence of an association between ELF EM fields and SIDS, but there is no support for the possibility that subterranean aquifers are implicated. This is almost entirely due to the original study design, which could not identify all subterranean aquifers, particularly those which are naturally occurring. Tests for significance confirm that in the 31 cases of SIDS in Inner London during 1986-88 near to clearly identified sources of ELF EM energy a linear correlation indicating a dose response relationship (Pearsons: r=0.983) was identified. A measured field study, possibly in a hospital special care baby unit, or in a densely populated urban area, may throw further light on the question, and our laboratory continues to seek funding for this study against a background of official procrastination, obfuscation, and denial of any relation between ELF electric fields and SIDS.

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