Association between tuberculosis, diabetes and 25 hydroxyvitamin D in Tanzania: a longitudinal case control study.
BACKGROUND
Vitamin D level is inversely associated with tuberculosis (TB) and diabetes (DM). Vitamin D could be a mediator in the association between TB and DM. We examined the associations between vitamin D, TB and DM.


METHODS
Consecutive adults with TB and sex- and age-matched volunteers were included in a case-control study in Dar es Salaam, Tanzania. Glycemia and total vitamin D (25(OH)D) were measured at enrolment and after TB treatment in cases. The association between low 25(OH)D (<75 nmol/l) and TB was evaluated by logistic regression adjusted for age, sex, body mass index, socioeconomic status, sunshine hours, HIV and an interaction between low 25(OH)D and hyperglycemia.


RESULTS
The prevalence of low 25(OH)D was similar in TB patients and controls (25.8 % versus 31.0 %; p = 0.22). In the subgroup of patients with persistent hyperglycemia (i.e. likely true diabetic patients), the proportion of patients with low 25(OH)D tended to be greater in TB patients (50 % versus 29.7 %; p = 0.20). The effect modification by persistent hyperglycemia persisted in the multivariate analysis (pinteraction= 0.01).


CONCLUSIONS
Low 25(OH)D may increase TB risk in patients with underlying DM. Trials should examine if this association is causal and whether adjunct vitamin D therapy is beneficial in this population.
Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania. noemie.boillat@chuv.ch.|Swiss Tropical and Public Health Institute, Basel, Switzerland. noemie.boillat@chuv.ch.|Department of Sciences, University of Basel, Basel, Switzerland. noemie.boillat@chuv.ch.|Infectious Diseases Service, Lausanne University Hospital, Lausanne, Switzerland. noemie.boillat@chuv.ch.
Noémie
N
Boillat-Blanco
Institute of Social and Preventive Medicine, Lausanne University Hospital, Lausanne, Switzerland.
Pascal
P
Bovet
Shree Hindu Mandal Hospital and Muhimbili University of Health Sciences, Dar es Salaam, United Republic of Tanzania.
Kaushik L
KL
Ramaiya
Kinondoni Municipal Council, National Tuberculosis Program, Dar es Salaam, United Republic of Tanzania.
Maliwasa
M
Mganga
Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania.
Lilian T
LT
Minja
Institute of Clinical Chemistry, University of Zurich, University Hospital of Zurich, Zurich, Switzerland.
Lanja
L
Saleh
Swiss Tropical and Public Health Institute, Basel, Switzerland.|Department of Sciences, University of Basel, Basel, Switzerland.
Medea
M
Imboden
Swiss Tropical and Public Health Institute, Basel, Switzerland.|Department of Sciences, University of Basel, Basel, Switzerland.
Christian
C
Schindler
Swiss Tropical and Public Health Institute, Basel, Switzerland.|Department of Sciences, University of Basel, Basel, Switzerland.
Sebastien
S
Gagneux
Swiss Tropical and Public Health Institute, Basel, Switzerland.|Department of Sciences, University of Basel, Basel, Switzerland.
Claudia
C
Daubenberger
Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania.|Swiss Tropical and Public Health Institute, Basel, Switzerland.|Department of Sciences, University of Basel, Basel, Switzerland.
Klaus
K
Reither
Swiss Tropical and Public Health Institute, Basel, Switzerland.|Department of Sciences, University of Basel, Basel, Switzerland.
Nicole
N
Probst-Hensch
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D016022:Case-Control Studies; D003920:Diabetes Mellitus / Q000453:epidemiology* / Q000378:metabolism; D005260:Female; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015995:Prevalence; D013636:Tanzania / Q000453:epidemiology; D014376:Tuberculosis / Q000453:epidemiology*; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*; D055815:Young Adult
D001786:Blood Glucose; D014807:Vitamin D; C104450:25-hydroxyvitamin D
Diabetes; Stress-induced hyperglycemia; Transient hyperglycemia; Tuberculosis; Vitamin D