Health consequences of physical inactivity greater in those with low socioeconomic status

People from low socioeconomic status areas who also had low levels of physical activity had worse health outcomes than those with low levels of physical activity from more affluent areas, according to researchers.

Susan Paudel, PhD, MPH, a postdoctoral research fellow at Deakin University in Australia, and colleagues wrote in the British Journal of Sports Medicine that “socioeconomic inequalities in health are a global challenge” and “signify a range of differences in socioeconomic status (SES) as determined by an individual’s economic and social position in relation to others, based on income, education, employment status or occupation and ethnicity.”

“Generally, individuals of low SES or those living in low socioeconomic areas have a higher prevalence of detrimental health-related behaviors and may have less favorable health outcomes such as higher morbidity and mortality,” they wrote.

The researchers conducted a prospective analysis to assess whether individual- and area-level SES status affect the association of sedentary behavior and physical activity with incident CVD and all-cause mortality.

Paudel and colleagues evaluated accelerometer-measured and self-reported sedentary behavior and physical activity data from 328,228 people — 45% of whom were men — enrolled in the U.K. Biobank. They used the Townsend Index as a measure of area-level SES and created an individual-level composite SES index with a latent class analysis of education, employment status and household income.

When it came to self-reported levels of moderate to vigorous physical activity, 15% were in the low group, 48.6% were in the medium group and 36.4% were in the high group.

The researchers found that low levels of physical activity and more sedentary behaviors led to an increased risk for all-cause mortality and incident CVD. When it came to SES, they noted statistically significant interactions for every exposure in the all-cause mortality analyses by individual-level SES.

“SES may influence an individual’s access to health information, treatment choices, compliance to treatment regimens, quality of care and social support, resulting in differential prognosis for similar risk factors or health conditions,” Paudel and colleagues wrote.

Additionally, compared with high self-reported physical activity, the adjusted HRs for all-cause mortality among the low physical activity group were:

• 1.14 (95% CI, 1.05-0.25) in the high individual-level SES group;
• 1.15 (95% CI, 1.06-1.24) in the medium individual-level SES group; and
• 1.22 (95% CI, 1.13-1.31) in the low individual-level SES group.

Notably, there were increased detrimental associations of low physical activity with decreasing area-level SES for both incident CVD and all-cause mortality.

“In our study, the detrimental associations of low physical activity and high sedentary behavior were more pronounced in low SES, suggesting that SES may interact with physical activity and sedentary behavior for mortality and incident CVD risks,” the researchers wrote. “This finding supports the vulnerability hypothesis, which suggests unhealthy lifestyles may inflict more harm in low socioeconomic groups and is consistent with studies on other unhealthy behaviors such as smoking and alcohol consumption.”

Paudel and colleagues concluded that “public health interventions targeting physical activity and sedentary behavior might need to focus on both low SES individuals as well as low SES areas for greater returns.”

“Further research is needed to establish this evidence and better understand the mechanisms underlying these findings,” they wrote.