Associations of socioeconomic status and health lifestyles with chronic obstructive pulmonary disease: two nationwide population-based studies

BACKGROUND: Low socioeconomic status (SES) is associated with increased chronic obstructive pulmonary disease (COPD) risk, with smoking and poor diet as major contributing factors. However, the impact of a comprehensive healthy lifestyle as a potential mediator between SES and COPD risk remains understudied. METHODS: This study analyzed data from 32,836 US adults in the NHANES (1999-2020) and 131,872 UK adults in the UK Biobank. SES was assessed via latent class analysis based on income, education, employment, and health insurance (NHANES). SES was categorized into high, middle, and low levels. Healthy lifestyle scores included nonsmoking, no heavy drinking, regular physical activity, and a high-quality diet. Weighted multivariable logistic regression (NHANES) and Cox proportional hazards models (UK Biobank) were used to assess the associations between SES and the prevalence (NHANES) or incidence (UK Biobank) of COPD. RESULTS: In the UK Biobank, the incidences of newly diagnosed COPD in the high-, medium-, and low-SES groups were 1.27%, 2.92%, and 6.57%, respectively. In the U.S. NHANES, the prevalence rates of COPD were 2.55%, 2.53%, and 4.50%, respectively. Compared with the highest SES group, a low SES was a risk factor for both the incidence and prevalence of COPD (UK Biobank: HR = 3.27, 95% CI = 2.98 to 3.58; NHANES: OR = 1.61, 95% CI = 1.23 to 2.10). The percentages of the mediation effect of a healthy lifestyle in the UK Biobank and US NHANES were 2.81% and 37.27%, respectively. Additionally, compared with those in the group with the highest SES and the healthiest lifestyle, the risk of COPD incidence and prevalence increased by 950% (HR = 10.50, 95% CI = 9.04 to 12.20) and 641% (OR = 7.41, 95% CI = 5.10 to 10.78), respectively, in the group with the lowest SES and the unhealthiest lifestyle. Risk factor analysis for COPD revealed that, in addition to a low SES (HR = 2.55, 95% CI = 2.39 to 2.72; OR = 2.08, 95% CI = 1.76 to 2.46) and unhealthy lifestyle (HR = 2.92, 95% CI = 2.73 to 3.12; OR = 3.78, 95% CI = 3.13 to 4.57), smoking (HR = 5.23, 95% CI = 4.87 to 5.61; OR = 3.85, 95% CI = 3.23 to 4.59) was the most significant risk factor for COPD. CONCLUSIONS: Low SES significantly contributes to COPD risk, but a healthy lifestyle mediating this association. Promoting healthy lifestyle choices and addressing socioeconomic disparities are essential public health strategies for COPD prevention. Additionally, smoking cessation and increased early screening in smokers are strongly recommended.