Season of birth and subsequent body size: The potential role of prenatal vitamin D

Abstract

The following explanatory mechanism has been formulated: insolation in Poland is minimal in November-February (winter period), and so ultraviolet absorption and vitamin D production is then the lowest. Vitamin D regulates embryo's cellular differentiation, and its deficiency triggers permanent developmental changes. Therefore, individuals conceived in autumn (i) are at the greatest risk of early vitamin D deficiency, (ii) are born in summer, and (iii) are relatively small in their further lives. The contribution of low-socioeconomic status, short breastfeeding, and being a male to the occurrence of the season-of-birth effect is also discussed.

Prenatal factors associated with the neonatal line thickness in human deciduous incisors

“…This influence concerns many biological features, among others: fecundity, conceptions and births (Leslie and Fry, 1989;Lam et al, 1994;Malina and Himes, 1977;Panter-Brick, 1996), sex ratio at birth (Nonaka et al, 1999), children's birth parameters (McGrath et al, 2005), infant mortality (Doblhammer and Vaupel, 2001), adult mortality (Moore et al, 1997), height and weight in later life (Banegas et al, 2001;Henneberg and Louw, 1993;Kościński et al, 2004;Krenz-Niedbała et al, 2011;Shephard et al, 1979;Weber et al, 1998), cardiovascular conditions in adulthood (Doblhammer and Vaupel, 2001;Painter et al, 2005), life expectancy and the probability of death at older ages (Doblhammer and Vaupel, 2001;Gagnon, 2012;Muñoz-Tudurí and García-Moro, 2008), and even the incidence of certain neurodegenerative diseases, such as multiple sclerosis (Doblhammer et al, 2005; G Model JCHB-25372; No. of Pages 13 Salzer et al, 2010;Wiberg and Templer, 1994;Willer et al, 2005) or Parkinson's disease (Gardener et al, 2010;Mattock et al, 1988).…”

“…Children born in winter are characterised on average by a thicker neonatal line compared with children born in summer and spring. In Poland, the highest insolation occurs from May to August with average insolation of 243.17 h per month (with the maximum recorded in June and July), and the lowest from November to February with average insolation of 50.42 h per month (Woś, 1999;Krenz-Niedbała et al, 2011). In the case of children born in winter, therefore, the third trimester of pregnancy when the greatest increase of total calcium level in a foetus is noted (Carpenter, 1999), and the first period of independent nutrition and vitamin D accumulation falls into months in which least solar radiation directly reaches the surface of the Earth.…”

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

“…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].…”

Vitamin D and Obesity

“…Similarly, measurements of BMI and waist circumference were higher in the winter than during the summer [22]. In Poland, boys born in October-April were taller (by 2-3 cm), heavier (by 2-3 kg), and fatter than boys born in May-September [23]; November-May is the winter period in Poland. In another study, people in the highest QFM had lower peak serum 25OHD 3 levels and smaller amounts of seasonal variation in serum 25OHD 3 levels than did those in the lowest QFM [24].…”