Association between vitamin D insufficiency and tuberculosis in a Vietnamese population.
BACKGROUND
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Department of Internal Medicine, Pham Ngoc Thach University of Medicine, Thanh Thai Street, District 10, Ho Chi Minh City, Vietnam. thuclanhopham@pnt.edu.vn
Lan T
LT
Ho-Pham
Nguyen D
ND
Nguyen
Tong T
TT
Nguyen
Dung H
DH
Nguyen
Phuong K
PK
Bui
Vien N
VN
Nguyen
Tuan V
TV
Nguyen
D016022:Case-Control Studies; D019411:Clinical Laboratory Techniques / Q000379:methods; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008297:Male; D008853:Microscopy; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D010281:Parathyroid Hormone / Q000097:blood; D013183:Sputum / Q000382:microbiology; D013194:Staining and Labeling / Q000379:methods; D014376:Tuberculosis / Q000453:epidemiology*; D014744:Vietnam / Q000453:epidemiology; D014808:Vitamin D Deficiency / Q000150:complications*
D010281:Parathyroid Hormone