Abstract
BACKGROUND: Since physical activity is an important determinant of physical and mental health, lower levels of physical activity among mothers reported in previous research are concerning. The aim of this study was to examine whether physical activity levels differ among mothers depending on the age of the youngest child. METHODS: Cross-sectional data from the German National Cohort study, comprising 3959 mothers aged 22-72 years with offspring aged 0-54 years (grouped into 0-5, 6-11, 12-17, 18-29 and > 30 years) was used. The Global Physical Activity Questionnaire (GPAQ) was used to assess physical activity among mothers in leisure time, transport and (occupational and non-occupational) work settings, quantified as MET-minutes per week. Means (with 95% confidence interval) of mothers' weekly MET-minutes were visualized in graphs, stratified by mothers' and the youngest child's age. Linear regression analyses assessed the association between the child's age and self-reported time and intensity of mothers' physical activity within each activity domain and for the total physical activity. RESULTS: Adjusted results suggested that the MET-minutes in work settings were lower among mothers with younger children. This association was clearest in mothers whose youngest child was under 12 years old, among whom lower self-reported physical activity at work compared to mothers with children at age 30 and older was found. No association was observed between the age of the youngest child and mothers' MET-minutes in leisure nor in transport settings. The self-reported physical activity of mothers whose youngest child was in the same child age group was found to be lower with increased maternal age. As expected, the work related activity dominated the self-reported physical activity. CONCLUSIONS: The results show differences in mothers' self-reported physical activity by the age of the youngest child. The strongest difference was related to physical activity in work settings, indicating the need for supportive actions.