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Brain drain: Smoking, not exercising, and two other habits could turn your brain to mush by the time you're ready to retire.

RODALE NEWS, EMMAUS, PA—The results of a large study tracking middle-aged men and women for nearly two decades found that four particular habits greatly predict how well your brain will function by the time you reach your 60th birthday.

THE DETAILS: The study, published in the American Journal of Epidemiology this month, looked at the health behaviors of 5,100 men and women, collecting information from them on three separate occasions: early midlife (average age of 44), midlife (average age of 56), and late midlife (average age of 61). Researchers tracked four health-related habits: tobacco, alcohol use, physical activity, and fruit and vegetable consumption.

Regardless of age, people scored worse on memory and brain-functioning tests if they engaged in unhealthy behaviors relating to the risk factors—such as smoking or not eating many fruits or vegetables. When compared to people with no unhealthy behaviors, those who had three or four bad habits faced a minimum of an 84 percent increased risk of scoring poorly on mental functioning tests. They also found that the people who partook in unhealthy habits longer faced more than twofold greater odds of poor memory and nearly a threefold increased chance of poor brain functioning. Interestingly, people who totally abstained from alcohol had a higher risk of problems than those who drank moderately. Those who consumed 5 to 14 units of alcohol a week performed better in brain and memory tests. (A unit is considered a pint of beer, glass of wine, or ounce of liquor.)