Living in Multi-Generational Household Increases Women's Risk of Heart Disease

By Kristina Fiore

OSAKA, Japan, 21 dec 2008 -- The stress of living with the in-laws and the kids could increase a woman's risk of serious heart disease, researchers reported here. Women living in multi-generational households had a two- to- three-fold higher risk of coronary heart disease compared with those who lived with only a spouse, H. Iso, M.D., of Osaka University, and colleagues reported online in Heart. The cause, said the researchers is "probably due to stress from multiple family roles," the researchers said. Previous studies have suggested that living in a multi-generational household -- a family structure that is prevalent in Japan -- could be both beneficial and stressful, the researchers said. Benefits include social support and shared care-giving, the researchers said, while meeting the demands of playing multiple roles -- as daughter, mother, and partner -- could have a detrimental effect. To examine the impact of such living arrangements on the incidence of heart disease and mortality, the researchers conducted the Japan Public Health Center-based Prospective (JPHC) study of 90,987 Japanese men and women ages 40 to 69. All participants were disease-free when they enrolled in the study between 1990 and 1994. They were surveyed regarding living arrangements, personal and family medical histories, perceived stress, occupation, personality, and diet and exercise. By the time the monitoring period ended in 2004, there were a total of 671 cases of coronary heart disease (506 men, 165 women), 339 deaths from coronary heart disease (242 men, 97 women), and 6,255 all-cause deaths (4,182 men, 2,073 women). In a multivariate analysis, women living with a spouse, children, and parents had a two-fold increased risk (95% CI 1.01 to 3.94) of coronary heart disease compared with women who lived only with a spouse. Parents seemed to cause more stress than children: Women who lived with a spouse and parents had a 3.03-fold increased risk of coronary heart disease (95% CI 1.36 to 6.75), and women living with a spouse and children had a 2.11-fold increased risk (95% CI 1.33 to 3.35). The same patterns were not seen among men living in multi-generational households, the researchers said. They also found that women living in multi-generational households were much less likely to engage in risky behaviors such as smoking or drinking compared with women living alone or with only a spouse. Yet women living in such households were more likely to report a higher prevalence of stress than those living alone or with only a spouse. The stress of playing multiple roles like daughter-in-law, mother, and partner could boost levels of stress hormones and inflammatory proteins that strengthen the effects of other risk factors such as hypertension and diabetes, the researchers said. Despite an increased risk of disease, the researchers found no association in either men or women between mortality from coronary heart disease and multi-generational family structure. Women living with their parents had an increased risk of coronary heart disease mortality (HR 4.94, 95% CI 1.95 to 7.32), but the estimate was based on only five cases. "This suggests that although living in multi-generational households may increase the risk of incident disease, it does not affect prognosis after established disease," the researchers said. The study was limited by self-reported data and the fact that coronary heart disease might be over- or underdiagnosed, the researchers said, but note that it is the first prospective study to examine the association between living arrangements and disease incidence within multi-generational families. They also noted the possibility of reverse causation in the subset living without a spouse. "Poor health status is a disadvantage in the marriage market, thereby leading to a preponderance of healthy subjects in the married population. Thus, men and women living only with parents or others may have been doing so because they were already sick, or were being cared for by family members. The increased risk of CHD mortality among both men and women living only with parents or others in this study might be due to such reverse causation." The study was supported by the Ministry of Health, Labor, and Welfare of Japan. The researchers reported no disclosures.

Primary source: Heart Source reference: Ikeda A, et al "Living arrangement and coronary heart disease: the JPHC study" Heart 2008; DOI: 10.1136/hrt.2008.149575.