Smoking history and physical performance in midlife: results from the British 1946 birth cohort

Abstract

Background: The adverse effects of smoking on individual medical conditions are well known; however, the cumulative effect of smoking on physical performance is not well characterized, particularly in midlife.

Methods: In the British 1946 Birth Cohort Study, cigarette pack-years were examined with standing balance, chair rising, grip strength, and an overall composite index. Pack-years were calculated from data collected at ages 20, 25, 31, 36, 43, and 53 years, whereas physical performance, cognitive function, anthropometry, and spirometry were assessed at age 53 years in 2,394 men and women. Regression and cubic splines were used to assess the relationship between pack-years and physical performance.

Results: Greater pack-years smoked were associated with lower overall physical performance and lower performance in standing balance and chair rising; however, there was no association with grip strength. For every 10 pack-years smoked, the overall physical performance index decreased by 0.11 SD (95% confidence interval: 0.07-0.15, p < .001), standing balance time decreased by 0.09 SD (0.05-0.13), and the reciprocal of chair rise time decreased by 0.11 SD (0.07-0.16). Adjustment for education, social class, lung function, cognitive function, and medical conditions attenuated the effect, but pack-years remained significantly associated with standing balance and chair rising time.

Conclusions: Lifetime cigarette pack-years are strongly related to physical performance in the fifth decade of life, suggesting that smokers will enter older adulthood with decreased physiological reserve. As smoking prevalence remains high in many developed countries and is rapidly growing in developing countries, these findings underscore the need for effective smoking cessation and prevention programs.

Figure 1.

Smoking data from the British 1946 birth cohort.

Figure 2.

Cigarette pack-years among smokers (upper x-axis shows percentiles) and frequency.

Figure 3.

Mean difference in four measures of physical performance (standard deviations unit) at age 53 years by lifetime cigarette pack-years among smokers. Adjusted for gender, height, and weight at 53 years (modeled using restricted cubic Splines with three knots). p Values are calculated using the Wald test. Shaded area is 95% confidence interval.