Determinants of Restrictive Spirometric Pattern in a Sub-Saharan Urban Setting: A Cross-sectional Population-based Study

Background Restrictive spirometric pattern is a risk factor for all-cause and cause-specific mortality. Objective We assessed the prevalence of restrictive pattern and investigated its determinants in a major sub-Saharan Africa city. Methods Participants were adults (≥ 19 years) who took part in a population-based survey in Yaounde (Cameroon) between December 2013 and April 2014. Restrictive pattern was based on a FVC below the lower limit of the normal (LLN) and a ratio forced expiratory volume in one second (FEV1)/FVC ≥ LLN (LLN-based restrictive pattern) or a FVC <80% and FEV1/FVC ≥ LLN (fixed cut-off based restrictive pattern). Determinants were investigated by logistic regressions. Results In all, 1003 participants [514 (51.2%) women] with a mean age of 33.7 years were included. The prevalence of restrictive pattern was 18.8% (95%CI: 16.6-21.2) based on LLN and 15.0% (13.0-17.2) based on fixed cut-off. LLN-based restrictive pattern was mild in 148 (78.3%) subjects, moderate in 35 (18.5%) and severe in 6 (3.2%). Determinants of LLN-based restrictive pattern were age ≥ 60 years [adjusted odds ratio 2.90 (95%CI 1.46-5.77), p=0.002), history of pulmonary tuberculosis [3.81(1.42-10.20), p=0.008], prevalent heart diseases [3.81 (1.20-12.12), p=0.024] and underweight [5.15(1.30-20.39), p=0.020]. Determinants were largely similar with slightly different effect sizes for fixed cut-off based restrictive pattern. Conclusion Restrictive pattern was very frequent in this city. Clinical implications These results enhance the needs to increase the efforts to prevent and control tuberculosis, cardiovascular diseases and underweight in this setting.