Season of birth in females with anorexia nervosa in Northeast Scotland.

OBJECTIVE: To determine whether patients with anorexia nervosa exhibit an abnormal pattern in their season of birth. METHOD: Case records of female patients presenting to secondary services in Northeast Scotland from 1965 to 1997 who received a clinical diagnosis of anorexia nervosa were examined. The months of birth of the 446 anorexic patients with a confirmed diagnosis were compared with 5,766 female control subjects born locally in 1951, 1961, 1971, and 1981. RESULTS: Patients with anorexia nervosa had an excess of births in the first 6 months of the year (p =.013). The greatest excess was from March to June. DISCUSSION: This provides further evidence that birth dates of anorexics peak in the late spring and early summer. There are parallels with the epidemiology of schizophrenia. The evidence suggests that a seasonally fluctuating factor, most plausibly an intrauterine effect of common infectious agents during the winter months, is of etiological significance.

Changes in the presenting features of females with anorexia nervosa in northeast Scotland, 1965-1991.

OBJECTIVE: Rates of anorexia nervosa among females presenting to specialist services in northeast Scotland had increased significantly between 1965 and 1991. We sought to elucidate possible causes of this change. METHOD: Hospital and primary care records were searched. Age, weight, and body mass index (BMI) were determined for 196 patients and duration of symptoms from onset to presentation was established in 190 cases. Changes in these parameters were investigated over the 27-year period of the study. RESULTS: There was no significant change in duration of illness or in age at presentation. BMIs increased significantly, but this arose because patients decreased in height, not because they increased in weight. There was no increase in seriously underweight patients with BMIs of < or =15. DISCUSSION: Anorexic females were not referred at an earlier stage of their illness, but primary care teams may be identifying and referring milder cases. Alternatively, the findings may reflect an increasing incidence of eating disorders coupled with changes in their presenting symptomatology.