Table 2:

Survey of Studies Concerned with Ambient Temperature Exposure and Anorexia

First Author, Year Study design: size, location, years	Exposures and method of assessment	Outcomes	Results	Key findings	Newcastle-Ottawa Quality Assessment Scale Score
Watkins, 2002 PMID: 12183938 Retrospective Study, 408 patients (259 diagnoses of anorexia nervosa, 149 other eating disorders) in the UK	Average monthly temperature at assumed time of conception was taken from meteorological records	Anorexia nervosa (early onset)	-Quarterly analysis identified April-June as the peak period in the birth pattern of patients with anorexia nervosa, but association failed to reach significance (x2=5.41; df=3; p=.144) -Mean temperature during the assumed month of conception for anorexia nervosa group was 101.1 C (SD= 4.82), versus 9.1 C (SD= 4/82) for the other eating disorders – this difference was significant (z=2.26; one-tailed p = 0.024)	Patients with anorexia nervosa were more likely to be born between April-June and more likely to be conceived during warmer months (July-September).	1/9
Willoughby, 2002 PMID: 12183942 Retrospective Study, 458 patients born in the UK and Australia between 1971 and 1990	Ambient temperature exposure was mean temperature during the month of assumed conception	Anorexia nervosa (including subtypes - restrictive, binge/purge)	-The chi-squared goodness of fit did not approach significance (x2 = 13.1; df = 11; p = .287) when assessing the monthly birth rates of Australians with anorexia nervosa as well as the seasonality effects in Australia based on quarterly birth patterns. - No significant associations between diagnosis and month of birth (x2 = 7.68; df-11; two-tailed p−.741) or quarter of birth (x2 = 4.45;df-3; two-tailedp-.217) -A proportionately lower number of restrictive anorexics (40/134; 30%) were conceived in cooler months (mean temperature ≤ 16.95 degrees C) relative to the number of binge/purge subtype anorexics born in warm months (23/54; 43%). This association was significant [x2(Yate's continuity correction)-2.81;df-1; one-tailed p−.047].	A significant link was found between temperature at the assumed time of conception and restrictive anorexia birth months for restrictive but not binge/purge anorexic subtypes in Australia were less likely to be conceived in relatively cool weather; i.e. more likely to be conceived in warm weather, supporting a temperature at conception hypothesis rather than a simple seasonal pattern of birth. There was little change across the year in the birth patterns of young people with anorexia nervosa in the southern hemisphere.	0/9
Waller, 2002 PMID: 12436015 Retrospective Study, 195 adult female anorexics, 117 being of the restrictive subtype and 78 being binge-purging subtype from three specialist eating disorders clinics in southeast England	Utilized Meteorological Office records of mean monthly temperatures for the central area of England.	Anorexia nervosa diagnosis, restrictive subtype and binge-purging subtype	-A significantly higher proportion of restrictive anorexics were born in the high-risk period (April through June) (chi-squared = 2.91, df = 1, one tailed p<0.5) and were more likely to be conceived in warm months (mean temperature > 14.1 degrees C) than cold or mild months (mean temperature <14.1 degrees C) -Among the 117 restrictive anorexics, 32 (27.4%) were born during the relatively warm months with only 12 (15.4%) of the 78 binge-purging anorexics born during the warm months -Restrictive anorexics born during the high-risk period (April – June) had slightly lower BMI (mean = 15.4, SD = 4.30) than the restrictive anorexics born during other months (mean = 15.9, SD = 3.23); this difference was not significant -No significant difference in BMI (Mann-Whitney z = .41, NS) between binge-purge anorexics born in April through June (mean = 17.3, SD = 2.12) and those born in other months (mean = 16.9, SD = 3.38) -Mean temperature at conception of the restrictive anorexics was 10.1 degrees C (SD = 4.80) while the mean for the binge-purge anorexics was slightly lower at 9.34 degrees C (SD = 4.21); difference was not statistically significant (Mann-Whitney z = 1.20, one-tailed p .12). -Restrictive eating attitudes (EAT-26 dieting and oral control scores) were significantly correlated with temperature at assumed conception but only among the restrictive anorexics.	Higher proportion of restrictive anorexics were born in the high-risk period - April through June (conceived July through September). Higher environmental temperature at assumed conception was more likely to be found in restrictive anorexics vs binge-purge subtype. Higher environmental temperature at assume conception was associated with more restrictive eating attitudes among restrictive anorexics only.	0/9