High prevalence of vitamin D deficiency in urban health checkup population.

Background: Vitamin D deficiency is documented as a common health problem in the world. Limited data has been found on the prevalence of vitamin D deficiency in Beijing area.

Aim: To investigate the prevalence s of vitamin D deficiency in urban Beijing residents and the seasonal and monthly serum 25(OH)D variation in this population.

Methods: This is an urban hospital based cross-sectional study lasting whole 2 years. 5531 (5-101 years old) urban Beijing residents for health checkup are recruited from December 9th, 2011 to December 8th, 2013. Each subject completed a questionnaire designed to quantify intake of vitamin D through food, vitamin D supplements, hours of sun exposure, sunscreen use over the past month. Serum 25(OH)D is statistically analyzed in accordance with gender, age, and time-lines.

Results: Vitamin D deficiency (Serum 25(OH)D level ≤20 ng/mL) and sever deficiency (Serum 25(OH)D level ≤ 10 ng/mL) are highly prevalent in this population. The prevalence of vitamin D deficiency is 87.1% and higher prevalence is found in female (89.0%) than male (84.9% P < 0.001). Severe vitamin D deficiency is also higher in female than male (59.3% and 42.7%, respectively, P < 0.001). Female under 20 and over 80 have lower 25(OH)D levels compared to 40-60 years old female (both P < 0.05). Severe vitamin D deficiency are also highly prevalence in this two group (60.9% and 54.1%) compared with 40-60 years old females (43.1%, both P < 0.05). Seasonal variation are also found in this population (P < 0.01). Autumn and summer have the higher 25(OH)D level than winter and spring in both genders (P < 0.001). Winter and spring have higher vitamin D deficiency and Severe deficiency than the other two seasons (P < 0.05). Serum 25(OH)D level peaks in October and troughed in April in both female and male. Lower serum 25(OH)D level are found in April than February (P < 0.05) in both gender.

Conclusions: This is the first time to examine the prevalence of vitamin D deficiency among urban Beijing residents spanning the age spectrum. And Vitamin D deficiency and severe deficiency is found highly prevalent in this population, especially among females under 20 and older than 80 and in winter and spring seasons. Targeted prevention on vitamin D deficiency is urgent for this population.