Interrelationships Between Vitamin D and Body Mass Index and Waist Circumference in Canada

Abstract

60 % of Canadians have suboptimal vitamin D (<75 nmol/L) and 25% are obese. Obesity has been reported to be a risk factor for low vitamin D, but there is uncertainty about the magnitude of the association. Linear regression was performed using data from the nationally representative cross-sectional Canadian Health Measures Survey (2007-2009). Height, weight, waist circumference (WC), and vitamin D levels were directly measured. There were 5298 participants aged 6 to 79 years. Using a conservative p value of 0.001, body mass index (BMI) category obese / obese I was positively associated and WC was inversely associated with vitamin D level in crude analysis. WC was inversely associated with vitamin D level in multivariate analysis. The pattern of relationship is not the same as other studies, yet this was a large study with direct measurements. There may be issues with linearity of relationships or subgroups disturbing the relationship.