Unequally Unequal? Contextual-level status inequality and social cohesion moderating the association between individual-level socioeconomic position and systemic chronic inflammation.

BACKGROUND: Status inequality is hypothesised to increase socioeconomic inequalities in health by creating an environment in which social cohesion erodes and social comparisons intensify. Such an environment may cause systemic chronic inflammation. Although these are often-used explanations in social epidemiology, empirical tests remain rare. METHODS: We analysed data from the West of Scotland Twenty-07 Study. Our sample consisted of 1977 participants in 499 small residential areas. Systemic chronic inflammation was measured by high-sensitivity C-reactive protein (hs-CRP; <10 mg/L). An area-level measurement of status inequality was created using census data and contextual-level social cohesion was measured applying ecometrics. We estimated linear multilevel models with cross-level interactions between socioeconomic position (SEP), status inequality, and social cohesion adjusted for age and gender. Our main analysis on postcode sector-level was re-estimated on three smaller spatial levels. RESULTS: The difference in hs-CRP between disadvantaged and advantaged SEPs (0.806 mg/L; p = 0.063; [95%CI: -0.044; 1.656]) was highest among participants living in areas where most residents were in advantaged SEPs. In these status distributions, high social cohesion was associated with a shallower socioeconomic gradient in hs-CRP and low social cohesion was associated with a steeper gradient. In areas with an equal mix of SEPs or most residents in disadvantaged SEPs, the estimated difference in hs-CRP between disadvantaged and advantaged SEPs was -0.039 mg/L (p = 0.898; [95%CI: 0.644; 0.566]) and -0.257 mg/L (p = 0.568; [95%CI: 1.139; 0.625]) respectively. In these status distributions, the gradient in hs-CRP appeared steeper when social cohesion was high and potentially reversed when social cohesion was low. Results were broadly consistent when using area-levels smaller than postcode sectors. CONCLUSIONS: Inequalities in hs-CRP were greatest among participants living in areas wherein a majority of residents were in advantaged SEPs and social cohesion was low. In other combinations of these contextual characteristics, inequalities in systemic chronic inflammation were not detectable or potentially even reversed.

Association of longitudinal alcohol consumption trajectories with coronary heart disease: a meta-analysis of six cohort studies using individual participant data.

BACKGROUND: Studies have shown that alcohol intake trajectories differ in their associations with biomarkers of cardiovascular functioning, but it remains unclear if they also differ in their relationship to actual coronary heart disease (CHD) incidence. Using multiple longitudinal cohort studies, we evaluated the association between long-term alcohol consumption trajectories and CHD. METHODS: Data were drawn from six cohorts (five British and one French). The combined analytic sample comprised 35,132 individuals (62.1% male; individual cohorts ranging from 869 to 14,247 participants) of whom 4.9% experienced an incident (fatal or non-fatal) CHD event. Alcohol intake across three assessment periods of each cohort was used to determine participants' intake trajectories over approximately 10 years. Time to onset for (i) incident CHD and (ii) fatal CHD was established using surveys and linked medical record data. A meta-analysis of individual participant data was employed to estimate the intake trajectories' association with CHD onset, adjusting for demographic and clinical characteristics. RESULTS: Compared to consistently moderate drinkers (males: 1-168 g ethanol/week; females: 1-112 g ethanol/week), inconsistently moderate drinkers had a significantly greater risk of incident CHD [hazard ratio (HR) = 1.18, 95% confidence interval (CI) = 1.02-1.37]. An elevated risk of incident CHD was also found for former drinkers (HR = 1.31, 95% CI = 1.13-1.52) and consistent non-drinkers (HR = 1.47, 95% CI = 1.21-1.78), although, after sex stratification, the latter effect was only evident for females. When examining fatal CHD outcomes alone, only former drinkers had a significantly elevated risk, though hazard ratios for consistent non-drinkers were near identical. No evidence of elevated CHD risk was found for consistently heavy drinkers, and a weak association with fatal CHD for inconsistently heavy drinkers was attenuated following adjustment for confounding factors. CONCLUSIONS: Using prospectively recorded alcohol data, this study has shown how instability in drinking behaviours over time is associated with risk of CHD. As well as individuals who abstain from drinking (long term or more recently), those who are inconsistently moderate in their alcohol intake have a higher risk of experiencing CHD. This finding suggests that policies and interventions specifically encouraging consistency in adherence to lower-risk drinking guidelines could have public health benefits in reducing the population burden of CHD. The absence of an effect amongst heavy drinkers should be interpreted with caution given the known wider health risks associated with such intake. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03133689 .