How Men Age May Be Predetermined at Midlife

JAMA

Why do some men live longer than others? This question was the impetus for a recent analysis of >5000 men, 655 of whom met the criteria for “exceptional survival” by living to age ≥85 years without major chronic conditions, showing that avoiding certain risk factors by midlife can predict living to older age (. 2006; 296:2343-2350).

Although exceptional survival was defined as ages 75 to 90, the study focused on age ≥85 as the target, since by that age American women outnumber their male counterparts by more than 2 to 1. Data for the 5820 men came from the Honolulu Heart Program/Honolulu Aging Study and was used to determine the risk factors that predispose some men to early mortality.

At enrollment (1965-1968), the men were in their midlife (45-68 years) and were free of morbidity and functional impairments. A 40-year follow-up was used to assess exceptional survival without any of 6 major chronic diseases (ie, coronary heart disease, stroke, cancer, chronic obstructive pulmonary disease, Parkinson disease, treated diabetes) and without physical/cognitive impairment.

The participants were initially grouped into 1 of 4 phenotypes: (1) nonsurvivors, (2) usual survivors but disabled, (3) usual survivors with major chronic disease but no disability, and (4) exceptional survivors.

Some 3369 (58%) of the men fell into the nonsurvivors group; 758 (13%) men fit into group 2: disease but no disability; and 1038 (18%) men fit into group 3. The men classified as exceptional survivors numbered 655 (11%). Because the risk factors for groups 2 and 3 were very similar, the groups were combined in the final analysis.

Stark contrasts were found across the groups for most risk factors. Exceptional survivors had:

• Stronger grip strength, suggesting that increased physiologic reserve and/or better physical fitness in midlife may help prolong survival

• A tendency to be thinner throughout their lifespan

• Lower levels of serum triglycerides, glucose, and uric acid.

Other factors affecting overall survival in men included:

• Smoking

• Overweight at midlife

• Alcohol consumption of ≥3 drinks daily

• Education, which was the most dominant sociodemographic characteristic of exceptional survivors.

Notably, nearly a 60% likelihood for exceptional survival was seen among men who had no risk factors at midlife. This percentage decreased to <10% among those with ?6 risk factors.

These data suggest that the probability of exceptional survival is as high as 69% with no risk factors, and as low as 22% in men with ≥6 risk factors.

&#8220;Only 11% of men actually met the criteria for exceptional survivorship at oldest-age in our cohort, suggesting possible room for improvement in an already long-lived population,&#8221; lead investigator Bradley J. Willcox, MD, and colleagues write.