Childhood urbanicity and hair steroid hormone levels in ten-year-old children

Abstract

Background: Research suggests that it may be more stressful for children to grow up in an urban area than in a rural area. Urbanicity may affect physiological stress system functioning as well as the timing of sexual maturation. The purpose of the current study was to investigate whether moderate urbanicity (current and childhood, ranging from rural areas to small cities) was associated with indices of long-term hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axis functioning (cortisol, cortisone, dehydroepiandrosterone and progesterone levels) and whether sex moderated any associations.

Method: Children (N = 92) were all 10 years old and from the Dutch general population. Hair samples were collected and single segments (the three cm most proximal to the scalp) were assayed for concentrations of steroid hormones (LCMS/MS method). Neighborhood-level urbanicity and socioeconomic status were measured from birth through age ten years. Analyses were controlled for neighborhood- and family socioeconomic status, body mass index and season of sampling.

Results: The results from multivariate analyses of variance showed no associations between current or childhood moderate urbanicity and hair steroid hormone concentrations. Interaction terms between moderate urbanicity and sex were not statistically significant.

Conclusions: Associations between urbanicity and steroid hormone levels may only be detectable in highly urban areas and/or during later stages of adolescence. Alternatively, our findings may have been due to most children being from families with a higher socioeconomic status.

Keywords: Children; HPA axis; Hair; Socioeconomic status; Steroid hormones; Urbanicity.