English summary: EFFECT OF MIDLIFE WEIGHT GAIN ON MORTALITY AND QUALITY OF LIFE IN OLD AGE

Background We assessed the impact of weight gain up to midlife on mortality and quality of life in old age in men.

Methods In the Helsinki Businessmen Study cohort, 1657 men born in 1919-1934 and with high socioeconomic status were followed up for 26 years. They had participated in health check-ups during the 1960s and were clinically healthy at baseline in 1974. Their body weight was recorded at the age of 25, as well as in 1974, 1985-1986 and 2000. Total mortality up to the year 2000 was retrieved from national registers. In 2000, we mailed a health questionnaire (including RAND-36 [SF-36] health related quality of life instrument) to all survivors (n = 1147, response rate 91%).

Results On the average, body weight increased from age 25 to midlife but not thereafter. During the follow-up, 392 men (23.7% of the baseline cohort) died. Weight at 25 years did not predict death, but the adjusted mortality risk was significantly higher in the highest quartile of weight gain (> 15 kg) compared to lower quartiles (RR 1.39, 95% CI 1.12-1.73). Weight gain up to midlife predicted worse scores in all eight RAND-36 domains in old age (statistically significantly worse in seven) after adjustments for weight at 25 years and in 1974, age, smoking, alcohol consumption and subjective health and fitness in 1974.

Conclusions In this homogenous male cohort only the highest weight gain up to midlife predicted long-term mortality. Instead, weight gain had a graded effect on the health-related quality of life in old age. Best quality of life was reported by those old men whose weight had not increased during adult life.