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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    • "Birth season is strictly related to environmental conditions to which the child was exposed to during pregnancy and its first months after birth (Bogin, 1999). Researchers emphasize primarily seasonal variations in insolation, and thus in the amount of vitamin D (Krenz-Niedbała et al., 2011; McGarth et al., 2006), but also dietary differences resulting from the availability of specific foodstuffs (Doblhammer and Vaupel, 2001). Other factors affecting development which display variation depending on the season include exposure to viruses and bacteria, air temperature (Murray et al., 2000), environmental pollution, and photoperiod-dependent melatonin production that inhibits growth hormone secretion (Waldie et al., 2000; Weber et al., 1998). "
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    ABSTRACT: Objectives: The purpose of this study was to determine whether the month of birth influences the maturation rate of Polish females from two birth cohorts, namely 1982-1984 and 1992-1994. It was also verified whether socioeconomic status (SES) is capable of altering the above relationship. Methods: The research material consisted of data collected in two cross-sectional surveys. The first cohort involved 1,008 female secondary-school students, the second, 671 female university students. Information on subjects' date of birth, SES, and the age at menarche was obtained from a questionnaire. The subjects were divided into four groups, according to the month of birth: born in spring (III-V), born in summer (VI-VIII), born in autumn (IX-XI), and born in winter (XII-II). Next, the subjects were divided into two groups: born in summer months (VI-VIII) and born in the other months (IX-V). Results: In the first cohort, subjects born in the summer reach menarche significantly earlier than subjects born in other seasons. The same tendency was noticeable in subjects born in the years 1992-1994; however, the differences were not statistically significant. In both cohorts, girls born in summer months had their first menstruation at a younger age than girls born in other months. The difference in age at menarche between season/months was also seen after dividing the data into uniform groups in terms of SES. Conclusion: The present data suggest that the season of birth influences sexual maturation rate in women. Am. J. Hum. Biol., 2015. © 2015 Wiley Periodicals, Inc.
    No preview · Article · Sep 2015 · American Journal of Human Biology
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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.
    Full-text · Article · Apr 2014 · American Journal of Physical Anthropology
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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.
    Full-text · Article · Sep 2013 · PLoS ONE
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