Jordan Lyerly1, MSPH, Elizabeth F. Racine2, DrPH, James Laditka2, PhD

1University of North Carolina Charlotte, Health Psychology Program

2University of North Carolina Charlotte, Department of Public Health Sciences

Maternal work hours during childhood and adolescent

obesity:A longitudinal analysis

Increase in adolescent obesity rates1 and mothers working outside the home2 in past 40 years

Rationale for relationshipRelationship between increased maternal

work hours and child and/or adolescent obesity3-8

Limitations of existing research

Background

Are increased hours of maternal employment associated with an increased rate of adolescent obesity?

How does income modify this relationship?

Research Questions

DataFrom the Panel Survey of Income Dynamics

(1997-2005) and Child Development Survey (1997-2007)

DesignLongitudinal

Participants1,108 adolescents and their parents

Methods – Design and Participants

Exposure – Maternal employment during childhoodHours/week worked by mothers over all 3 time

points (i.e. during childhood)Outcome – Adolescent obesity

Weight and height measured by trained staffConsidered obese if BMI > 95th percentile based on

sex and ageModifying variable– Income

Based on the poverty level, considered9:Low income (< 200% of poverty level)Middle income (201%-400% of poverty level)High income (>400% poverty level)

Methods - Measures

Adjusted discrete time series analysisRelative risk95% confidence intervalsConsidered several potential covariates

Maternal age, maternal education, maternal obesity, marital status, income, child sex, child birth weight, and child physical activity level

Interaction between maternal work hours and income

Methods-Analysis

At baseline (1996)Median age of child – 3.5 yrsMedian maternal work hrs/wk – 30Median paternal work hrs/wk – 45Income

42.7% low income32.0% middle income

25.4% high income

In 200720.7% of adolescents were obese

Results: Descriptives

RR 95% CI

Maternal work hrs/wk 1.75 1.01-3.03

Paternal work hrs/wk 1.00 0.61-1.09

Maternal Work Hours by income

0-200% PL vs not 1.45 0.76-2.79

201-400% PL vs. not 2.74 1.15-6.53

≥ 401% PL vs. not 2.17 0.53-8.86

Results: Adjusted Relative Risk

• No interactive effect of paternal work hours and income on risk of adolescent obesity.

• Maternal obesity was also associated with an increased risk of adolescent obesity (RR = 2.89, 95% CI=2.16-3.87)

As maternal work hours increased, the risk of adolescent obesity increased

Income modified this relationshipThe association between maternal work hours

and adolescent obesity was particularly strong among middle income families

There was no association between paternal work hours and risk of adolescent obesity

Conclusion

StrengthsLongitudinal data with detailed information

regarding employment and incomeMeasured height and weightExtended research by examining how income

modifies the relationshipLimitations

AttritionDoes not address causal mechanism

Strengths and limitations

Better support and services for working mothers to assist in promoting healthy behaviors in children

Interventions could address ideas and support for:Quick and healthy mealsHealthy eating practices for children

Focus groups with mothers from different income levels to understand barriers to healthy eating

Implications

1. Ogden, C., & Carroll, M. Prevalence of obesity among children and adolescents: United States, trends 1963-1965 through 2007-2008. In: NCHS Health and Stats: National Center for Health Statistics; 2010.

2. US Department of Labor. Women in the laborforce: A databook. http://www.bls.gov/cps/wlf-databook-2012.pdf

3. Anderson, P. M., Butcher, K. F., & Levine, P. B. (2003). Maternal employment and overweight children. Journal of Health Economics, 22, 477-504.

4. Fertig, A., Glomm, G., & Tchernis, R. (2009). The connection between maternal employment and childhood obesity: Inspecting the mechanisms. Review of Economics of the Household, 7, 227-255.

5. Hawkins, S. S., Cole, T. J., & Law, C. (2008). Maternal employment and early childhood overweight: Findings from the UK Millennium Cohort Study. International Journal of Obesity, 32(1), 30-38.

6. Morrissey, T. W. (2012). Trajectories of growth in body mass index across childhood: Associations with maternal and paternal employment. Social Science and Medicine, in press.

7. Von Hinke Kessler Scholder, S. (2008). Maternal employment and overweight children: Does timing matter? Health Economics, 17, 889-906.

8. Ziol-Guest, K. M., Dunifon, R. E., & Kalil, A. (2012). Parental employment and children’s body weight: Mothers, others, and mechanisms. Social Science and Medicine, in press.

9. National Center for Health Statistics. Health, United States, 2010: With Special Feature on Death and Dying. Hyattsville, MD. 2011.

References