Vitamin D status is associated with muscle strength and quality of life in patients with COPD: a seasonal prospective observation study

Abstract

BackgroundOwing to hospitalization, reduced functional capacity and consequently, less sunlight exposure, suboptimal vitamin D status (25-hydroxyvitamin D [25(OH)D]⩽50 nmol/L) is prevalent among COPD patients.ObjectiveThis study aimed to investigate seasonal changes in vitamin D status and any associated changes in fat-free mass (FFM), muscle strength and quality of life (QoL) in COPD patients.Patients and methodsCOPD patients living in Northern Ireland (n=51) completed study visits at the end of winter (March/April) and at the end of summer (September/October), corresponding to the nadir and peak of vitamin D status, respectively. At both time points, serum concentration of 25(OH)D was quantified by liquid chromatography-tandem mass spectrometry, FFM (kg) was measured using bioelectrical impedance and muscle strength (kg) was measured using handgrip dynamometry. QoL was assessed using the validated St George’s Respiratory Questionnaire.ResultsMean±SD 25(OH)D concentration was significantly higher at the end of summer compared to the end of winter (52.5±30.5 nmol/L vs 33.7±28.4 nmol/L, P<0.001); and house- bound patients had significantly lower 25(OH)D concentration compared to nonhousebound patients at the end of summer (42.9±4.2 vs 57.2±9.9 nmol/L; P⩽0.001). Muscle strength (at both time points) and QoL (end of summer only) were positively predicted by 25(OH)D concentration, independent of age, sex and smoking status.ConclusionThis study highlights the need for health policies to include a recommendation for year-round vitamin D supplementation in housebound COPD patients, and wintertime supplementation in nonhousebound patients, to maintain optimal 25(OH)D concentrations to protect musculoskeletal health. Furthermore, an optimal vitamin D status may have potential benefits for QoL in these patients.

Comparison of the Association between Circulating Vitamin D₃ Levels and Clinical Outcomes in Patients with Asthma and Chronic Obstructive Pulmonary Disease: A Prospective Observational Study

“…Our results support the findings of previous cross-sectional studies which did not find associations between vitamin D status and general and COPDspecific HR-QOL scores, including EQ-5D scores and the St. George's Respiratory Questionnaire, in COPD patients. [22][23][24] By contrast, it is interesting to observe that in COPD patients, lower concentrations of plasma 25(OH) D 3 contributed to lower lung function, corresponding to increased COPD severity, in agreement with previous studies. [25][26][27][28] Moreover, the multivariate model indicated that the decrease of plasma 25(OH) D 3 level was independently associated with future exacerbations after lung function was added as a covariate.…”

Vitamin D deficiency is associated with respiratory symptoms and airway wall thickening in smokers with and without COPD: a prospective cohort study

“…A small randomized, placebo-controlled trial of sixty-two patients hospitalized with acute exacerbation of COPD in Iran showed significant improvement in SGRQ total score at day 30 and day 120 following hospital admission, vitamin D supplementation and normalization of vitamin D concentration [21]. Another small trial of fifty-one patients in Northern Ireland showed improved SGRQ total score with higher vitamin D levels [22]. Our data similarly showed vitamin D deficiency was associated with higher SGRQ total score, indicating worse quality of life, and higher MMRC score, consistent with increased dyspnea.…”

Correlation of severity of chronic obstructive pulmonary disease with serum vitamin-D level

“…Study has shown that muscle strength and quality of life are positively predicted by vitamin-D concentration independent of age, sex, and smoking status. [34] In addition to this, loss in exercise capacity can also be explained by the sarcopenia and loss of muscle strength as a consequence of Vitamin D deficiency. [34]…”

“…[34] In addition to this, loss in exercise capacity can also be explained by the sarcopenia and loss of muscle strength as a consequence of Vitamin D deficiency. [34]…”