Communities Exposed to Adverse Socioeconomic Factors Found to Sleep Less, Have Increased Risk of Cardiovascular Disorders

The association between disadvantaged communities and heightened risk of cardiovascular disease (CVD) was attributed to factors that impair sleep quality and duration, such as living in noisy environments, working several jobs with various shifts, and having greater levels of emotional and financial stress, according to a study published last week in Cardiovascular Research.

Among people affected by socioeconomic inequalities, insufficient sleep has been observed in the past, with associations with adverse health outcomes such as CVD. However, as the researchers note, the contribution of sleep to socioeconomic inequalities in CVD is unclear, warranting an analysis to find specific catalysts for CVD risk. In African Americans, stressors such as discrimination were found to contribute to a heightened level of chronic stress, which raised the risk of hypertension and further highlighted the impact of socioeconomic status.

Researchers conducted the first large population-based study to examine whether inadequate sleep could potentially explain why disadvantaged communities exhibit higher CVD incidence. The study derived cross-sectional data from 8 European cohorts (n = 111,205) and delineated life-course socioeconomic status through assessments on father’s and adult occupational position, which were categorized as low (lower clerical, sales workers, skilled/unskilled workers), medium (small employers and self-employed, farmers, lower supervisors, and technicians), and high (higher professionals/managers, lower professionals/managers, higher clerical). They considered the following:

• Self-reported sleep duration categorized as recommended (6—8.5 hours per night), long (>8.5 hours per night), and short (<6 hours per night)
• Adverse cardiovascular outcomes included coronary heart disease (CHD) and stroke
• Primary endpoints, including the association between life-course socioeconomic status and CVD, and the contribution of sleep duration to this measurement using counterfactual mediation

For analyses on a participant’s father’s occupation, a low position was associated with an increased 19% CHD risk among men and 25% among women participants (men: odds ratio [OR], 1.19; 95% CI, 1.04-1.37; women: OR, 1.25; 95% CI, 1.02-1.54). After accounting for the participant’s occupational position, marginal decreases of CHD risk were shown in both men (OR, 1.17; 95% CI, 1.02-1.54) and women (OR, 1.22; 95% CI, 0.99-1.52), with no mediating effect by short sleep duration.

For participants who were categorized as having a low occupational position, a stark 48% increased risk of CHD was observed in men (OR, 1.48; 95% CI, 1.14-1.92), as was a 53% increased risk in women (OR, 1.53; 95% CI, 1.04-2.21). In this analysis, short sleep duration significantly contributed to the association between adult occupational position and CHD in men (13.4% mediation).

Stroke was not linked to any of the variables examined in the study.

Lead study author Dusan Petrovic, MSc, University General Medicine and Public Health Center in Lausanne, Switzerland, explained that the absence of mediation by short sleep in women could be attributed to the weaker relationship between occupation and sleep duration compared to men, but as shown in the data, women remain at a higher risk of CHD regardless. “Women with low socioeconomic status often combine the physical and psychosocial strain of manual, poorly paid jobs with household responsibilities and stress, which negatively affects sleep and its health-restoring effects compared to men,” said Petrovic.

To combat the adverse effects caused by socioeconomic status, Petrovic provided suggestions to address prominent stressors. "Structural reforms are needed at every level of society to enable people to get more sleep. For example, attempting to reduce noise, which is an important source of sleep disturbances, with double glazed windows, limiting traffic, and not building houses next to airports or highways," said Petrovic.

Reference

Petrovic D, Haba-Rubio J, Vargas CDM, et al. The contribution of sleep to social inequalities in cardiovascular disorders: a multi-cohort study. [published online November 22, 2019]. Cardiovasc Res. doi: 10.1093/cvr/cvz267.