High Prevalence of Hypovitaminosis D in Patients Presenting with Proximal Muscle Weakness: A Sub-Himalayan Study

Hypovitaminosis D has emerged as a major public health problem and 25-50% of patients encountered in clinical practice are deficient in vitamin D. This study was conducted to estimate the prevalence of hypovitaminosis D among patients presenting with proximal muscle weakness.

It was a cross-sectional study done on patients ≥18 years presenting in outdoor clinic from May 2008 to April 2013, with difficulty in standing and going up stairs/ diffuse musculoskeletal pains. Proximal muscle weakness due to other causes were excluded through investigations and those taking steroids and/or indigenous drugs were also excluded. Vitamin D levels measured by radioimmunoassay (RIA) in all eligible patients and individuals included in the study were those with hypovitaminosis D (<30ng/dl) and proximal muscle weakness. Patients reassessed after supplementation with vitamin D at 2 and 6 months.

99 patients with hypovitaminosis D associated proximal myopathy included in study. Of these 55 (55.55%) were males and 44 (44.44%) were females. Age ranged from 22 to 82 years with a mean of 52.84 ± 12.6 years. Of 99 patients, 55 (55.55%) were from the rural area and 44 (44.44%) from urban area. Mean duration of symptoms was 22.7 months (range 6-60 months). The level of 25(OH) Vitamin D ranged from 2.0 ng/dl to 35.7 ng/dl with the mean level of 13.18 ± 5.80 ng/dl (males = 12.76± 4.85ng/dl and females = 13.60±6.70ng/dl). Hypovitaminosis D was present in 98.98%. A direct relationship was found between the vitamin D levels (<10 ng/dl) and severity of weakness. Of 83 patients, who reported at the end of two and six months of treatment, 71 (85.54%) patients were able to stand-up from squatting position.

Muscle weakness is common among vitamin-D deficient individuals. Our study indicates that more focus should be on muscle symptoms in at risk population groups. The vitamin D deficiency related myopathy should not be missed due to its potential reversibility with vitamin D supplementation.