Seasonality of birth in children and young adults (0–29 years) with type 1 diabetes in Ukraine

Abstract

Aims/hypothesis Numerous epidemiological studies have shown differences in seasonality of birth patterns between the general population and the group who develop type 1 diabetes mellitus. This finding indicates that environmental factors operating during pre-and/or postnatal development could be aetiologically important. We examined whether the pattern of month of birth for type 1 diabetes patients in Ukraine differs from that for total live births. Methods Data consist of prevalent cases of type 1 diabetes in Ukraine by the end of 2003. Cases are restricted to persons born after 1 January 1960, diagnosed with type 1 diabetes before the age of 30 years (n=20,117). People born during the same time in the general population (n=29,105,560) were the reference standard. Seasonal patterns were estimated using logistic regression with harmonic terms. Results We found a strongly significant seasonal pattern of type 1 diabetes incidence rates (p<0.001), with the lowest rates in December and the highest in April. The rate ratio between the extremes was 1.32 (95% CI 1.27-1.39). Tests for seasonal patterns in subgroups defined by sex and age or by sex and date of birth were all significant with p values less than 0.02. We found no interactions with sex (p=0.142) or age at diagnosis (p=0.207), but found a strong interaction with period of birth (p<0.0001). Conclusions/interpretationThe results obtained indicate that early-life factors linked to seasons may influence type 1 diabetes risk later in life.

Association of Type 1 Diabetes With Month of Birth Among U.S. Youth

“…Similar reports have come from several regions of Europe (1–4), from New Zealand (where spring occurs in September–November) (5), and from Israeli Jews (6). This pattern was not demonstrated, however, by some studies elsewhere in Europe (3), in East Asia (7,8), or in Cuba (9).…”

Epidemiology of Type 1 Diabetes

“…This birth month effect was not observed in youth recruited from the centers in the more southern locations (South Carolina, Hawaii, Southern California), but only in the more northern latitudes (Colorado, Washington, and Ohio)54. A report from Ukraine also reported a strong seasonal birth pattern with the lowest rates of T1D in December and the highest in April55. Similar reports of higher rates of T1D among youth born in Spring and lower rates among youth born in the Fall have been published from Europe55–58, New Zealand59, and Israel60, but not in other studies from Europe, East Asia or Cuba58,61–63.…”

Season of the first trimester of pregnancy predicts sensitisation to food allergens in childhood: a population-based cohort study from Finland

“…The ratio between the highest and lowest predicted incidence rate was taken as the estimated relative amplitude of the seasonal variation. The 95% confidence limits for the amplitude were approximated by a parametric bootstrap simulation based on the pooled results of the fitted model 18 19. For further details, see the statistical appendix.…”