Married mothers who also hold jobs, despite having to juggle career and home, enjoy better health than their underemployed or childless peers. Data from a long-term study launched in the U.K. in 1946 shows that such working moms are the least likely to be obese by middle age and the most likely to report generally good health. And this result cannot be explained simply because the healthiest women take on the most.

Epidemiologist Anne McMunn of University College London drew more than 1,400 female participants from a study of 5,362 Britons born during the first week of March 1946. Followed throughout their lives, including face-to-face interviews at ages 26, 36, 46 and 53, the women provided data from both their own views of their health as well as objective measures such as body-mass index. By assessing both subjective and objective information, the researchers hoped to discover whether working moms undertook such multitasking because of their inherent health or achieved good health because of their multiple roles.

Of the 555 working mothers, only 23 percent proved obese by age 53, compared to 38 percent of the 151 full-time homemakers, who also averaged the highest body-mass index of all six categories of women, rounded out by single working mothers, the childless, multiply-married working moms and intermittently-employed married mothers. In addition, full-time homemakers reported the most poor health, followed by single mothers and the childless.

Of course, the data do not show why working moms are healthiest but the women's view of their own health at 26 did not correlate with whether they undertook both careers and families, seeming to discount a definitive role for good health in determining a woman's choices. Working correlated with low body mass in all groups, including single moms and childless women.

"Our results suggest that good health is more likely to be the result, rather than the cause, of multiple role occupation," the researchers write in a paper presenting the findings in the Journal of Epidemiology and Community Health. "The next step is to better understand what it is about particular work and family roles that influences people's health."