Are Mothers’ Working Hours Associated with General and Abdominal Obesity in Children and Adolescents? The Korean National Health and Nutrition Examination Survey (2008–2012)

Objectives Despite an increase in the female work force and recent increase in childhood obesity, the association between working hours of mothers and childhood obesity as well as how such association differs according to mothers’ weight and intake frequency of energy-dense, nutrition-poor (EDNP) foods remain unclear. Methods Data from the Korean National Health and Nutrition Examination Survey (2008–2012) that included samples from 3914 children in 2526 households were analyzed. Two-level (household-children) mixed-effects modeling was performed to investigate the association between mothers’ working hours and childhood obesity based on body mass index (BMI) and waist circumference (WC). Results Long working hours (h) of mothers were associated with both BMI (β = − 0.14; P = 0.324 for 1–20 h, β = 0.10; P = 0.334 for ≤ 21–40 h; β = 0.09; P = 0.429 for 41–68 h, β = 0.51; P = 0.015 for ≥ 69 h) and WC of the child (β = 0.06; P = 0.809 for 1–20 h; β = 0.46; P = 0.017 for ≤ 21–40 h; β = 0.59; P = 0.004 for 41–68 h, β = 1.35; P < 0.001 for ≥ 69 h), and the mean increase was greater for mothers working ≥ 69 h compared to those working 0 h. We also observed that the association between mothers’ working hours and child’s BMI and WC was greater for children whose mothers were either overweight or obese and frequently consumed energy-dense, nutrient-poor foods (EDNP). Conclusions for Practice Long working hours of mothers are associated with higher BMI and WC in children. Thus, it is important to improve labor welfare for mothers who work long hours, and provide interventions to promote good health behaviors in both children and working mothers.