Evaluation of pulmonary function tests and vitamin D level in pre and postmenopausal women

To assess the increased risk of vitamin D deficiency in postmenopausal women, and its correlation with pulmonary function decline in both premenopausal and postmenopausal women.

The cross-sectional, comparative study was conducted at the Physiology Department, Federal Postgraduate Medical Institute, Shaikh Zayed Hospital, Lahore, Pakistan, from May 2019 to May 2020. Healthy premenopausal women having regular menstrual cycles aged at least 40 years were placed in group 1, while healthy postmenopausal women having no menstruation for the preceding 12 months with maximum age 55 years were placed in group 2. Serum vitamin D levels were determined using enzyme-linked immunosorbent assay, and pulmonary functions by spirometry. Groups 1 and 2 were divided into hypovitaminosis and vitamin D-sufficient subgroups 1A, 1B, 2A and 2B. Data was analysed using SPSS 21.

Of the 120 female subjects, 60(50%) were in each group. Mean age in years of group 1(premenopausal group) was 46.03±2.35. Mean age in years of group 2 (postmenopausal group) was 52.72±1.43. Mean body mass index was 23.0± 2.59kg/m2 in group 1 compared to 24.14±2.76kg/m2 in group 2. Mean serum vitamin D level was 42.91±16.94ng/ml in group 1, and 27.42±6.70ng/ml in group 2 (p=0.001). The percentage predicted value of age for forced expiratory volume in 1 second, forced vital capacity, and the ratio between the two in group 1 were 82.95±2.75%, 83.10±2.65% and 0.998±0.003% respectively. In group 2, the corresponding values were 79.48±1.20%, 79.12±1.40% and 1.004±0.010% (p<0.05). The values for forced expiratory volume in 1 second, forced vital capacity, and the ratio between the two were significantly different in subgroups 1B and 2B compared to 1A and 2A (p<0.05).

Vitamin D deficiency was found to be related to the deterioration of pulmonary functions in both premenopausal and postmenopausal groups.