Season of birth is associated with anthropometric and neurocognitive outcomes during infancy and childhood in a general population birth cohort

Department of Psychiatry, University of Queensland, St Lucia QLD, Australia.
Schizophrenia Research (Impact Factor: 3.92). 02/2006; 81(1):91-100. DOI: 10.1016/j.schres.2005.07.017
Source: PubMed


The 'season of birth' effect is one of the most consistently replicated associations in schizophrenia epidemiology. In contrast, the association between season of birth and development in the general population is relatively poorly understood. The aim of this study was to explore the impact of season of birth on various anthropometric and neurocognitive variables from birth to age seven in a large, community-based birth cohort. A sample of white singleton infants born after 37 weeks gestation (n = 22,123) was drawn from the US Collaborative Perinatal Project. Anthropometric variables (weight, head circumference, length/height) and various measures of neurocognitive development, were assessed at birth, 8 months, 4 and 7 years of age. Compared to summer/autumn born infants, winter/spring born infants were significantly longer at birth, and at age seven were significantly heavier, taller and had larger head circumference. Winter/spring born infants were achieving significantly higher scores on the Bayley Motor Score at 8 months, the Graham-Ernhart Block Test at age 4, the Wechsler Intelligence Performance and Full Scale scores at age 7, but had significantly lower scores on the Bender-Gestalt Test at age 7 years. Winter/spring birth, while associated with an increased risk of schizophrenia, is generally associated with superior outcomes with respect to physical and cognitive development.

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    • "Season of birth correlates with the season at conception, the trimesters of pregnancy, and early infancy: short-or long-term seasonal growth effects could act during any of these times. Furthermore, seasonal variations in a range of environmental parameters are correlated, such as food availability , activity, morbidity, temperature, day length, and UV intensity, and can elicit complex and correlated behavioral responses (McGrath et al., 2006; Chodick et al., 2009). This makes it difficult to confidently identify causal relationships between seasonal environmental variation and phenotype. "
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    ABSTRACT: Associations between season of birth and body size, morbidity, and mortality have been widely documented, but it is unclear whether different parts of the body are differentially sensitive, and if such effects persist through childhood. This may be relevant to understanding the relationship between early life environment and body size and proportions. We investigated associations between birth month and anthropometry among rural highland (n = 162) and urban lowland (n = 184) Peruvian children aged 6 months to 8 years. Stature; head-trunk height; total limb, ulna, tibia, hand, and foot lengths; head circumference; and limb measurements relative to head-trunk height were converted to internal age-sex-specific z scores. Lowland and highland datasets were then analyzed separately for birth month trends using cosinor analysis, as urban conditions likely provide a more consistent environment compared with anticipated seasonal variation in the rural highlands. Among highland children birth month associations were significant most strongly for tibia length, followed by total lower limb length and stature, with a peak among November births. Results were not significant for other measurements or among lowland children. The results suggest a prenatal or early postnatal environmental effect on growth that is more marked in limb lengths than trunk length or head size, and persists across the age range studied. We suggest that the results may reflect seasonal variation in maternal nutrition in the rural highlands, but other hypotheses such as variation in maternal vitamin D levels cannot be excluded. Am J Phys Anthropol, 2014. © 2014 Wiley Periodicals, Inc.
    American Journal of Physical Anthropology 04/2014; 154(1). DOI:10.1002/ajpa.22484 · 2.38 Impact Factor
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    • "Interestingly, the season of birth has already been related to cognitive and physical characteristics in healthy controls. Notably, a study which analysed the cognitive and physical outcome of healthy children depending on their season of birth revealed a superior cognitive and physical development in winter and spring-born children compared to summer and autumn-born children [58]. Moreover, higher schizotypal traits and a tendency of lower agreeableness were found in healthy controls born during winter months compared to those born in the remainder of the year [59], [60]. "
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    ABSTRACT: In schizophrenia there is a consistent epidemiological finding of a birth excess in winter and spring. Season of birth is thought to act as a proxy indicator for harmful environmental factors during foetal maturation. There is evidence that prenatal exposure to harmful environmental factors may trigger pathologic processes in the neurodevelopment, which subsequently increase the risk of schizophrenia. Since brain white matter alterations have repeatedly been found in schizophrenia, the objective of this study was to investigate whether white matter integrity was related to the season of birth in patients with schizophrenia. Thirty-four patients with schizophrenia and 33 healthy controls underwent diffusion tensor imaging. Differences in the fractional anisotropy maps of schizophrenia patients and healthy controls born in different seasons were analysed with tract-based spatial statistics. A significant main effect of season of birth and an interaction of group and season of birth showed that patients born in summer had significantly lower fractional anisotropy in widespread white matter regions than those born in the remainder of the year. Additionally, later age of schizophrenia onset was found in patients born in winter months. The current findings indicate a relationship of season of birth and white matter alterations in schizophrenia and consequently support the neurodevelopmental hypothesis of early pathological mechanisms in schizophrenia.
    PLoS ONE 09/2013; 8(9):e75508. DOI:10.1371/journal.pone.0075508 · 3.23 Impact Factor
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    • "Moreover, most studies on the relationship between body height and weight and birth season showed that bigger were those individuals whose early fetal life fell on the period of high insolation [(Kos´cin´ski et al., 2004; McGrath et al., 2006; Puch et al., 2008; Puch and Kozłowska-Rajewicz , 2004; Shephard et al., 1979; Weber et al., 1998); but compare studies from the southern hemisphere: (Henneberg and Louw, 1990, 1993; Waldie et al., 2000)]. "
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    ABSTRACT: The relationship between season of birth and various physical and psychological outcomes was reported in many studies, although the underlying mechanism still remains unrecognized. The aim of this study was to explore the season-of-birth effect on body size in the sample of 1,148 eight-year-old Polish urban children and propose the mechanism responsible for this effect. The children were examined three times at their birthdays and at two cross-sectional surveys. Effects of the season of birth were checked by fitting the cosine function to empirical values and by comparison between two groups born in different periods of the year. Data gathered at three examinations led to the same results: season-of-birth effect occurred only in boys and only in those relatively shortly breastfed and/or descended from the families of low-socioeconomic status. Specifically, the individuals born in October-April were taller (by 2-3 cm), heavier (by 2-3 kg), and fatter than those born in May-September. 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.
    American Journal of Human Biology 03/2011; 23(2):190-200. DOI:10.1002/ajhb.21101 · 1.70 Impact Factor
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