Parental nonstandard work schedules during infancy and children’s BMI trajectories

BACKGROUND Empirical evidence has demonstrated adverse associations between parental nonstandard work schedules (i.e., evenings, nights, or weekends) and child developmental outcomes. However, there are mixed findings concerning the relationship between parental nonstandard employment and children’s body mass index (BMI), and few studies have incorporated information on paternal work schedules. OBJECTIVE This paper investigated BMI trajectories from early to middle childhood (ages 3–11) by parental work schedules at 9 months of age, using nationally representative cohort data from the United Kingdom. This study is the first to examine the link between nonstandard work schedules and children’s BMI in the United Kingdom. METHODS We used data from the Millennium Cohort Study (2001‒2013, n = 13,021) to estimate trajectories in BMI, using data from ages 3, 5, 7, and 11 years. Joint parental work schedules and a range of biological, socioeconomic, and psychosocial covariates were assessed in the initial interviews at 9 months. 1 University College London (UCL), UK. E-Mail: [email protected]. 2 Institut national de la santé et de la recherche médicale (Inserm), France. 3 University of Cambridge, UK. 4 University of Southampton, UK. 5 University College London (UCL), UK. Zilanawala et al.: Parental nonstandard work schedules during infancy and children’s BMI trajectories 710 http://www.demographic-research.org RESULTS Compared to children in two-parent families where parents worked standard shifts, we found steeper BMI growth trajectories for children in two-parent families where both parents worked nonstandard shifts and children in single-parent families whose mothers worked a standard shift. Fathers’ shift work, compared to standard shifts, was independently associated with significant increases in BMI. CONCLUSIONS Future public health initiatives focused on reducing the risk of rapid BMI gain in childhood can potentially consider the disruptions to family processes resulting from working nonstandard hours. CONTRIBUTION Children in families in which both parents work nonstandard schedules had steeper BMI growth trajectories across the first decade of life. Fathers’ nonstandard shifts were independently associated with increases in BMI.