Association between vitamin D insufficiency and tuberculosis in a vietnamese population
1 Department of Internal Medicine, Pham Ngoc Thach University of Medicine, Thanh Thai Street, District 10, Ho Chi Minh City, Vietnam
2 People's Hospital 115, Thanh Thai Street, District 10, Ho Chi Minh City, Vietnam
3 MEDIC Medical Center, 254 Hoa Hao Street, District 10, Ho Chi Minh City, Vietnam
4 Pham Ngoc Thach Hospital for Tuberculosis, 120 Hong Bang Street, District 5, Ho Chi Minh City, Vietnam
5 Osteoporosis and Bone Biology Program, Garvan Institute of Medical Research, 384 Victoria Street, Sydney, NSW 2010, Australia
6 School of Public Health and Community Medicine, University of New South Wales, Sydney, NSW 2052, Australia
7 St Vincent's Clinical School, University of New South Wales, Victoria Street, Sydney, NSW 2010, Australia
BMC Infectious Diseases 2010, 10:306 doi:10.1186/1471-2334-10-306Published: 25 October 2010
Recent in vitro evidence suggests a link between vitamin D status and the risk of tuberculosis (TB). This study sought to examine the association between vitamin D status, parathyroid hormone (PTH) and the risk of TB in a Vietnamese population.
The study was designed as a matched case-control study, which involved 166 TB patients (113 men and 53 women), who were age-and-sex matched with 219 controls (113 men and 106 women). The average age of men and women was 49 and 50, respectively. TB was diagnosed by the presence of acid-fast bacilli on smears from sputum, and the isolation of M. tuberculosis. All patients were hospitalized for treatment in a TB specialist hospital. Controls were randomly drawn from the general community within the Ho Chi Minh, Vietnam. 25-hydroxyvitamin D [25(OH)D] and PTH was measured prior to treatment by an electrochemiluminescence immunoassay (ECLIA) on a Roche Elecsys. A serum level of 25(OH)D below 30 ng/mL was deemed to be vitamin D insufficient.
The prevalence of vitamin D insufficiency was 35.4% in men with TB and 19.5% in controls (P = 0.01). In women, there were no significant differences in serum 25(OH)D and serum PTH levels between TB patients and controls. The prevalence of vitamin D insufficiency in women with TB (45.3%) was not significantly different from those without TB (47.6%; P = 0.91). However, in both genders, serum calcium levels in TB patients were significantly lower than in non-TB individuals. Smoking (odds ratio [OR] 1.25; 95% confidence interval [CI] 1.10 - 14.7), reduced 25(OH)D (OR per standard deviation [SD]: 1.14; 95% CI 1.07 - 10.7) and increased PTH (OR per SD 1.13; 95% CI 1.05 - 10.4) were independently associated with increased risk of TB in men.
These results suggest that vitamin D insufficiency was a risk factor for tuberculosis in men, but not in women. However, it remains to be established whether the association is a causal relationship.