Objective: To estimate hypertension prevalence, describe regional and seasonal patterns of ambient air-pollution exposure in Croatia, and examine pollutant–hypertension associations while accounting for clustering. Design and method: Cross-sectional study, part of the nationwide EH-UH 2 project, utilized a representative random sample of 1,670 adults (>=18 years). Blood pressure (BP) was measured in the office according to the ESH guidelines. Hypertension (HTN) was defined as systolic BP >=140 mmHg and/or diastolic BP >=90 mmHg or treatment with antihypertensive drugs. Pollutants included PM2.5, PM10, SO2, O3, NO2, and NOx, collected as daily mean and monthly/annual mean/max., (30 metrics) from the Ministry of Environmental Protection and Green Transition. County–date (CD) exposure assignment defined 24 CD clusters. Exposures were summarized using participant- and CD-weighted approaches; prevalence used Wilson 95% confidence intervals. Associations were assessed with logistic regression using cluster-robust SE: Model 0 (crude), Model 1 (age, sex, BMI, smoking, and temperature matched to the exposure window), and Model 2 (Model 1 + education, urban/rural residence, NaCl intake, dyslipidaemia, diabetes, eGFR, cholesterol, and Na/K ratio). Stability was evaluated by Leave-One-Cluster-Out (LOCO) for Model 2; WHO annual-mean exceedance was also quantified. Results: HTN prevalence was 59.8% (95% CI 57.4–62.1), WHO annual-mean guideline values were exceeded (participant-weighted): PM2.5>5 μg/m3 in 100%, PM10>15 μg/m3 in 91.9%, and NO2>10 μg/m3 in 82.9% of participants. In regression analyses, PM10 annual maximum was positively associated with HTN in Model 1 (OR=1.025, 95% CI 1.021–1.028), but was based on 8 clusters, limiting interpretability. Daily mean SO2 showed positive associations in Models 0–1 (OR=1.20; 95% CI 1.05–1.37 and 1.11–1.30) but attenuated in Model 2 (OR=1.12; 95% CI 0.95–1.33). Other pollutants showed no or inverse associations; no metric was statistically significant in Model 2. LOCO analyses indicated sensitivity of several estimates to omission of single clusters, consistent with a limited effective sample size at the cluster level. Conclusions: Croatia has a high HTN burden and exceeds WHO air-quality guidelines. Fully adjusted clustered models showed limited evidence of independent pollutant–HTN links. SO2 signals in less adjusted models and cluster sensitivity suggest follow-up studies using finer exposure resolution and larger between-cluster variation.
Nikić et al. (Fri,) studied this question.