METHOD: One hundred RA patients and 50 healthy controls, sex- and age-matched, were recruited. Disease Activity Score of 28 joints and Health Assessment Questionnaire scores were assessed. Baseline serum 25(OH)D3 and IL-6 were measured in all subjects. RA patients who were vitamin D deficient were given loading doses of vitamin D3 and repeated assessments were done.
RESULTS: Vitamin D deficiency (<50 nmol/L) was found in 63% of RA patients and 76% of healthy controls. Chinese RA patients and healthy controls had significantly more sufficient 25(OH)D3 levels compared to Malays and Indians (P
METHODS: One hundred and ninety-seven healthy women, aged 25 to 60, were selected from a hospital staff health screening program; 68% were Chinese, 18% Malay, and 14% Indian. P1NP, CTX, and 25-OHD(3) were measured using the Roche Cobas® electrochemiluminescence immunoassay. Serum PTH was measured using the Siemens ADVIA Centaur® immunoassay.
RESULTS: Sixty-five percent had 25-OHD(3) concentrations <50 nmol/l. Vitamin D insufficiency (25-OHD(3) < 50 nmol/l) was more prevalent in Malays (89%) and Indians (82%) compared to Chinese (56%). There was no correlation between vitamin D and age. PTH positively correlated with age, and Malays and Indians had higher PTH concentrations than Chinese. There was an inverse correlation between PTH and 25-OHD(3), but no threshold of 25-OHD(3) concentrations at which PTH plateaued. The bone turnover markers P1NP and CTX inversely correlated with age but were not different between ethnic groups. CTX and P1NP exhibited good correlation, however, there was no significant correlation between 25-OHD(3) or PTH concentrations and the bone turnover markers P1NP and CTX.
CONCLUSIONS: Healthy women in Singapore have a high prevalence of vitamin D insufficiency. Vitamin D insufficiency was more prevalent in Malays and Indians compared to Chinese.