The Relationship Between Maternal Work Schedule And Overweight/Obesity Of Children Under 2 Years Of Age In China

BackgroundWith the rapid development of China’s economy and society and the needs of national life,women work has become a development trend.In 2000,the employment rate of women aged 25-54 reached 81.6%.The overweight/obesity among children has become increasingly serious in China,with 10.4 percent of children aged 0-5 years old overweight/obesity in 2017.Previous studies(United States and Australia)have shown that both maternal working hours and non-standard working hours may increase risk of overweight/obesity of children.However,this effect may varied among children from different countries economic,social and cultural of family and regions and countries.Therefore,the conclusions of foreign studies may not be simply extrapolated or applied to China.Children under 2 years of age are a critical period for the prevention and control of childhood overweight/obesity.Mothers and caregivers play an irreplaceable role in the prevention and control of childhood overweight/obesity.However,there is a lack of research on the relationship between maternal working hours and children’s overweight/obesity.Therefore,it is of great theoretical and practical significance to supplement relevant gaps for the prevention and control of childhood overweight/obesity in China.ObjectiveThe objectives of this study were(1)to analyze relationship between maternal working hours and overweight/obesity of children under 2 years of age in China;(2)to analyze relationship between mother worked at non-standard hours and risks of overweight/obesity of children under 2 years of age in China;(3)to explore the potential mechanism of the maternal working hours affecting weight of children under 2 years of age;(4)to analyze the similarities and differences in relationship between maternal working hours and overweight/obesity in Chinese children under 2 years of age in 2002 and 2020.MethodsThe information of maternal working hours and mothers’ nonstandard work schedules were collected through a questionnaire for children under 2 years of age and their parents from the survey of the "China National Nutrition and Health Systematic Survey for 0-18 years old Children and Utilization of Survey Findings"(Hereinafter referred to as the 2020 survey).It also collected potential confounders on the relationship between maternal working hours and child’s overweight/obesity and obtained children’s height and weight through anthropometric measurements.Subjects were stratified into two groups according to whether the mother is the main caregiver in all analyses.Logistic regression models was applied to analyze relationship between maternal working hours and the child’s overweight/obesity status.Confounders were controlled in the analysis.The relationship between maternal working hours and child’s overweight and obesity was further analyzed by stratified analysis of maternal education level and living in urban or rural areas.Then sensitivity analysis was conducted after excluding children whose mothers worked more than 5 days a week.Propensity score matching(PSM)was applied to obtain a control group with a 1:1 match for each child whose mother worked at non-standard hours.By adjusting the confounding factors,the exact logistic regression model was used to analyze the relationship between mothers who worked at non-standard hours and overweight/obesity of children under 2 years of age in China.Relationship of maternal working hours on feeding behavior and physical activity of children were explored.The path analysis method and structural equation model were used to explore the potential mechanism of maternal working hours on overweight/obesity of children under 2 years of age in China.The information of maternal working hours in 2002 was calculated based on the information collected from the physical activity questionnaire in the "China Nutrition and Health Survey(CNHS 2002,hereinafter referred to as the 2002 survey)".Height and weight of children under 2 years of age and confounding factor data consistent with those in 2020 were extracted.A database of children under 2 years of age and their mothers in 2002 was established,and logistic regression model was used to analyze the relationship between maternal working hours and a child’s overweight/obesity.Then the analysis was stratified by gender,urban and rural areas,family economic situation,and maternal education level.Relationship between maternal working hours and overweight/obesity of Chinese children under 2 years of age in 2002 and in 2020 was compared.Results1.Relationship between maternal working hours and overweight/obesity of children under 2 years of age in China1.1 Children whose mothers were the primary caregiverChildren whose maternal working hours were no more than 40 hours per week had a higher risk of overweight/obesity than children whose mothers were not working,and the OR value(95%CI)was 1.55(1.03-2.32).For mothers with a higher level of education or living in urban areas,stratified analysis showed that children whose maternal working hours were no more than 40 hours per week had a higher risk of overweight/obesity than children whose mother were not working,and the OR value(95%CI)were 1.8(1.01-3.20)and 1.69(1.02-2.80),respectively.There was no statistically significant difference in the risk of overweight/obesity in children whose maternal working hours were more than 40 hours per week compared with children whose mothers were not working.1.2 Children whose mothers were not the primary caregiverMaternal working hours were not associated with risks of child overweight/obesity.2.Analyze relationship between mother worked at non-standard hours and overweight/obesity of children under 2 years of age in ChinaWhen whose mothers were the primary caregiver,children whose mother worked at non-standard hours were not associated with overweight/obesity,and the OR value(95%CI)was 1.62(0,39-6.76).Same for children whose mothers were not primary caregiver,and the OR value(95%CI)was 0.63(0.39-1.06).3.Explore potential mechanism for relationship between maternal working hours and weight for length z-scores of children under 2 years of agePath analysis results showed that children whose maternal working hours were no more than 40 hours per week had a negative correlation with the Weight-for-length z-scores(WHZ)of children aged 0-5 months(β=-0.008,P=0.004)than children whose mother were not working.It might be that the weaning rate of 0-5 months old children whose maternal working hours were no more than 40 hours per week was higher and the daily outdoor activity time was longer(β=0.107,P<0.001;β=0.061,P=0.002).Children whose maternal working hours were no more than 40 hours per week had a positive correlation with the WHZ of children aged 6-11 months(β=0.007,P=0.032)than children whose mothers were not working,possibly because children aged 6-11 months whose maternal working hours were no more than 40 hours per week had a shorter sleep time(β=-0.106,P<0.001).Children whose maternal working hours were no more than 40 hours per week had a positive correlation with the WHZ of children aged 12-23 months(β=0.064,P=0.006)than children whose mother were not working,which may be due to their shorter sleep time,a lower proportion of supplementary food,and a higher weaning rate(β=-0.140,P<0.001;β=-0.185,P<0.001;β=0.183,P<0.001).4.Compare and analyze the similarities and differences in relationship between maternal working hours and obesity in Chinese children under 2 years of age in 2002 and 2020Children whose maternal working hours were no more than 40 hours per week had a higher risk of overweight/obesity than children whose mothers were not working in 2020.However,there was no significant difference in 2002,and the OR value(95%CI)was 1.17(0.73-1.89).Stratified analysis results showed that children whose mothers had higher education level and urban children whose maternal working hours were no more than 40 hours per week had a higher risk of overweight/obesity than children whose mother were not working in 2020,children whose mothers with higher education level and whose maternal working hours were no more than 40 hours per week had a higher risk of overweight/obesity than children whose mother were not working in 2002,and the OR value(95%CI)was 6.17(1.15-33.10).The risk of overweight/obesity for children whose maternal working hours were more than 40 hours per week was not statistically different from that of children whose mothers were not working in 2020.However,children whose maternal working hours were more than 40 hours per week had a lower risk of overweight/obesity than children whose mothers were not working in 2002,and the OR value(95%CI)was 0.51(0.30-0.90).Stratified analysis results showed that children whose mothers had less education level and rural children and boys whose maternal working hours were more than 40 hours per week had a lower risk of overweight/obesity than children whose mother were not working in 2002,and the OR value(95%CI)was 0.4(0.22-0.74),0.42(0.22-0.80)and 0.38(0.16-0.86),respectively.Conclusion1.When mothers were the primary caregiver of children,children whose maternal working hours were no more than 40 hours per week had a higher risk of overweight/obesity than children whose mothers were not working,especially for those with higher education levels or living in urban areas.When the mother was not the primary caregiver,the relationship was not significant in this research.There might be no significant association between children whose mothers worked at non-standard hours and risk of overweight/obesity when children whose mothers were the primary caregiver,but further confirmation is needed in large sample studies.2.Explore potential mechanism for relationship between maternal working hours were no more than 40 hours per week and weight for length z-scores of children under 2 years of age:Children whose maternal working hours were no more than 40 hours per week might mainly affects the weight for length z-score of children aged 0-5 months through children’s weaning and daily outdoor activity time;mainly affects the weight of children aged 6-11 months by affecting the sleep time of children;mainly affects the weight of children aged 12-23 months by affecting children’s sleep time,supplementary food and weaning.3.The relationship between maternal working hours and child’s overweight/obesity may not be consistent in different ages.