Seasonality of birth in adult type 2 diabetic patients in three Ukrainian regions

Abstract

To the Editor: Epidemiological studies have repeatedly shown a link between poor fetal growth and increased risk of developing type 2 diabetes [1]. Month of birth is a good instrument for the assessment of effects of early growth on adult health independent of life-course factors. This is true because in decades past there were important seasonal differences in nutrition, especially in developing countries such as Ukraine. These differences in access to high-quality food supply can potentially influence intrauterine growth, depending on the month of gestation [2]. Other possible triggering factors for developing type 2 diabetes, such as production of vitamin D [3] and outdoor temperature [4], also tend to change seasonally.Seasonal pattern of birth in type 1 diabetic children and adolescents was repeatedly described around the world, including our recent study in Ukraine [5]. In contrast, the seasonality of birth in type 2 diabetic patients was previously reported only in a few small-sample studies, e.g. in 155 African-American type 2 diabetic adolescent [6] and 282 adult patients in the Netherlands [7]. To study whether abnormal seasonality of birth exists in middle-to old-aged type 2 diabetic patients in Ukraine, we compared the month-of-birth patterns in type 2 diabetic patients in three large Ukrainian regions with those in general populations.Information on date of birth, sex and year of diagnosis was extracted from the nationwide primary-care-based Ukrainian diabetes mellitus register created in 2000 in the Institute of Endocrinology, Kiev, Ukraine. The definition of type 2 diabetes was based on onset after 39 years of age, irrespective of the type of treatment.Cases were identified from the three regional diabetes registers with high completeness of ascertainment: Chernigiv (100%), Kherson (99.7%) and Rivne (86.2%). These registers cover 7.4% of the total Ukraine population. A female excess was evident in all three registers. Cases were all people alive with diagnosis of type 2 diabetes as of 1 January 2008, and who were diagnosed at age 40 or later. Only people born before 1 January 1960 were included; thus all cases included were at least 48. In total, 17,510 male and 34,704 female type 2 diabetic patients were finally included in the study. Reference populations were based on the Ukraine census 2001 depersonalised data. These populations included people who had been born during the same period and were residents of the same regions: Chernigiv, 247,253 men and 369,357 women; Kherson, 208,944

Season of birth and the risk of type 2 diabetes in adulthood: a prospective cohort study of 0.5 million Chinese adults

“…Findings from a Dutch hospital-based series study of 282 patients aged 30-90 years with type 2 diabetes showed an excess of diabetes births in the first quarter of the year and a deficiency in the final quarter when comparing the month of birth with the standard birth curve [9]. In another study conducted in three regions of Ukraine, a variation in season of birth was observed in 52,214 individuals with type 2 diabetes who were born before 1960, with a peak in April and a nadir between November and December, compared with the month-of-birth patterns in the general population [10]. The only prospective study conducted in a Danish population-based cohort of 223,099 adults born between 1930 and 1989 showed no association between birth seasonality and risk of type 2 diabetes [11].…”

“…Factors exhibiting seasonal variation include, but are not limited to, exposure to sunlight, food availability and eating habits, and outdoor physical activity [4][5][6][7][8]. Only a few studies conducted in white populations living in relatively high-latitude regions have examined the association between the season or month of birth and type 2 diabetes in adulthood, with mixed results [9][10][11].…”

No evidence of seasonality of birth in adult type 2 diabetes in Denmark

“…Birthweight has been found to vary according to the season of birth, with peaks in birthweight in both autumn and summer [6,7], and it has been suggested that risk of type 2 diabetes displays a similar seasonal variation depending on the month of birth [8][9][10]. Indeed, studies in American children [10] and in adult populations in the Netherlands [8] and Ukraine [9] have reported seasonal variations in type 2 diabetes development according to month of birth.…”

“…Indeed, studies in American children [10] and in adult populations in the Netherlands [8] and Ukraine [9] have reported seasonal variations in type 2 diabetes development according to month of birth. The lowest type 2 diabetes prevalence in these studies was observed in people born in October to December, and the highest prevalence was in people born in January to April.…”

Prevalence of Type 1 Diabetes Correlates with Daily Insulin Dose, Adverse Outcomes and with Autoimmune Process Against Glutamic Acid Decarboxylase in Adults

“…In particular our studies of T2D patients (Khalangot et al, 2009 b ) indicate that Hazard Ratios (HRs) of cardiovascular disease (CVD) mortality among extremely obese patients [body mass index (BMI) ≥ 35 kg/m 2 ] adjusted for age, smoking and alcohol consumption were higher than for overweight patients [BMI 25-29 kg/m 2 ]: HR=1.54 (95% CI 1.16-2.05) and 1.35 (95% CI 1.15-1.59) among men an women respectively, p<0.01. Furthermore, the graph that shows risks of general and CVD mortality for T2D patients depending on BMI has the shape of an asymmetric parabola: HRs associated with low and normal BMI were significantly higher comparing to those, related to overweight or moderate obesity.…”