Social Disadvantage Is Associated With Lower Vitamin D Levels in Older People and There Is No Surrogate for Its Measurement

Abstract

Introduction: There is increasing evidence concerning adverse health consequences of low vitamin D levels. We determined whether there is any surrogate for measuring vitamin D in people older than 70 years and the relation between index of multiple deprivation (IMD) and vitamin D levels. Methods: Blood samples from 241 patients were included in this analysis. Concurrent measurements for 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH), and bone profile are reported. Results: The prevalence of total vitamin D insufficiency/deficiency (defined as total vitamin D <50 nmol/L) was 57.5% overall. Even for patients with vitamin D deficiency, a significant proportion had PTH, normal calcium, phosphate, and alkaline phosphatase levels. For patients with vitamin D <25 nmol/L, 62.7% had a PTH within reference range, 83.1% had normal serum-adjusted calcium, 80.6% had normal phosphate, and 85.1% had a normal serum alkaline phosphatase. With increasing quintiles of IMD, there was a 22% increased risk of vitamin D deficiency/insufficiency from quintiles 1 to 5, in age- and sex-adjusted logistic regression models (odds ratio [OR] = 1.22, 95% confidence interval [1.01, 1.47]; p = .034). Conclusion: No other parameter is currently adequate for screening for vitamin D deficiency in older people. A higher IMD is associated with lower vitamin D levels in older people.