Clustering of lifestyle risk factors and poor physical function in older adults: the Hertfordshire cohort study

Objectives: To examine the relationship between number of lifestyle risk factors (out of low physical activity, poor diet, obesity, smoking) and physical function in older community-dwelling men and women.

Design: Cross-sectional study, Hertfordshire, United Kingdom.

Participants: Men (n = 1,682) and women (n = 1,540) aged 59 to 73.

Measurements: Physical activity was assessed using an administered questionnaire with a score from 0 to 100; low activity was defined as a score of 50 or less. Diet was assessed using a food frequency questionnaire; diet quality was assessed according to a score for a principal component analysis-defined "healthy" dietary pattern. Poor diet was categorized as a dietary pattern score in the lowest quarter of the distribution. Obesity was defined as a body mass index of 30.0 kg/m(2) or more. Physical function was assessed according to self-report (SF-36); poor function was defined as a score in lowest quarter of the distribution. A subgroup of participants had objective assessments of physical function (Timed Up-and-Go Test, timed 3-m walk, chair rises, one-legged standing balance).

Results: There was a graded increase in prevalence of poor self-reported physical function in men and women with increasing number of risk factors (men, adjusted odds ratio (AOR) for 3 or 4 risk factors vs none = 3.79, 95% confidence interval (CI) = 2.31-6.21; women, AOR = 5.37, 95% CI = 2.66-10.84). With the exception of balance, the objective assessments also showed graded relationships with number of risk factors, such that more risk factors was associated with poorer physical function.

Conclusion: These modifiable lifestyle risk factors are linked to marked differences in risk of poorer physical function in older adults. Efforts to encourage healthy lifestyles have the potential to improve physical function and to promote healthier ageing.