Spirometric Lung Function Patterns Across Body Mass Index Categories in Ghana: A Tertiary Care Perspective

Overweight and obesity are rising rapidly in low- and middle-income countries, including Ghana, with growing implications for respiratory health. Body mass index (BMI) influences respiratory mechanics and lung function, yet its relationship with spirometric abnormalities remains poorly characterised in sub-Saharan Africa. This study assessed the distribution of BMI and its association with spirometric patterns among patients undergoing spirometry at a tertiary respiratory centre in Ghana.

A retrospective cross-sectional study was conducted using all spirometry tests performed between 2018 and 2025 at Komfo Anokye Teaching Hospital. Demographic and anthropometric data were extracted from medical records. Spirometric patterns were classified as normal, obstructive, probable restrictive or mixed. Logistic regression was used to evaluate the association between BMI categories and obstructive and probable restrictive ventilatory defects. Adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were reported.

Among 557 spirometry tests, the median age was 42 years (IQR: 28-61 years), and 311 (55.83%) participants were female. Probable restrictive lung patterns predominated (183, 32.85%), followed by mixed (71, 12.75%) and obstructive patterns (67, 12.03%). The median BMI was 24.4 kg/m² (IQR: 21.4-29.2 kg/m²), whereas nearly half of the participants were overweight or obese (46.31%). Obesity was more common among females than males (28.62% vs. 11.79%; p < 0.001). Crude analysis demonstrated increased odds of probable restrictive ventilatory defects among obese participants (OR = 1.87, 95% CI [1.18-2.96], p = 0.007), but this association was attenuated after adjustment (aOR = 1.45, 95% CI [0.90-2.35], p = 0.127). No BMI category was independently associated with obstructive ventilatory defects.

Abnormal spirometric findings were common, with probable restrictive ventilatory defects accounting for nearly one-third of all examinations. BMI was not independently associated with obstructive or probable restrictive ventilatory defects. These findings suggest that factors beyond body mass contribute to impaired lung function in this population and highlight the need for comprehensive respiratory assessment, including lung volume measurements where feasible.