Researchers identify risk factors for healthy survival in men

Nov 14 2006

Avoiding health risk factors in midlife such as smoking, being overweight, excessive drinking and hypertension is associated with a longer and healthier life in men, according to a study in the November 15 issue of JAMA: The Journal of the American Medical Association, a theme issue on men's health.

Bradley J. Willcox, M.D., of the Pacific Health Research Institute and Kuakini Medical Center in Honolulu, presented the findings of the study today at a JAMA media briefing on men's health in New York.

Persons alive at age 85 years or older are the fastest-growing age group in most industrialized countries and are among the largest consumers of health care resources. Identifying strategies for remaining healthy, vigorous, and disability-free at older ages has become a major priority, according to background information in the article. Studies with substantial numbers of long-lived participants and characteristics associated with longer survival are rare but essential to identify risk factors for health and survival at older ages.

Dr. Willcox and colleagues examined potential biological, lifestyle, and sociodemographic risk factors present at middle-age to identify risk factors for healthy survival. The study included 5,820 Japanese-American middle-aged men (average age, 54) in the Kuakini Honolulu Heart Program/Honolulu Asia Aging Study. The participants were free of illness and functional impairments and were followed for up to 40 years (1965-2005) to assess overall and exceptional survival. Exceptional survival was defined as survival to a specified age (75, 80, 85, or 90 years) without incidence of 6 major chronic diseases and without physical and cognitive impairment. The diseases were coronary heart disease, stroke, cancer (excluding nonmelanoma skin cancer), chronic obstructive pulmonary disease, Parkinson disease, and treated diabetes. Of the 5,820 original participants, 2,451 participants (42 percent) survived to age 85 years and 655 participants (11 percent) met the criteria for exceptional survival to age 85 years.

The researchers found that high grip strength and avoidance of overweight, hyperglycemia, hypertension, smoking, and excessive alcohol consumption were associated with both overall and exceptional survival. In addition, high education and avoidance of hypertriglyceridemia (elevated triglyceride level) were associated with exceptional survival, and lack of a marital partner was associated with death before age 85 years.

Risk factor models based on cumulative risk factors (survival risk score) suggest that the probability of survival to age 85 years is as high as 69 percent with no risk factors and as low as 22 percent with 6 or more risk factors. The probability of exceptional (healthy) survival to age 85 years was 55 percent with no risk factors but decreased to 9 percent with 6 or more risk factors

"Anthropometric [measurement and study of the human body and its capacities] measures from this study, such as grip strength, suggest that it is important to be physically robust in midlife. This is consistent with theories of aging that suggest that better-built organisms last longer and that physiological reserve is an important determinant of survival," the authors write. This may also be a marker of physical fitness.

"In summary, we have identified several potentially important risk factors for healthy survival in a large group of middle-aged men. These risk factors can be easily measured in clinical settings and are, for the most part, modifiable. This study suggests that common approaches that target multiple risk factors simultaneously, such as avoidance of smoking or hypertension, and approaches that enhance insulin sensitivity, such as maintaining a lean body weight, may improve the probability of better health at older ages. This may be especially important for men, few of whom survive to oldest-old age," the researchers conclude.