Predictors of body composition changes during tuberculosis treatment in Mwanza, Tanzania

BACKGROUND/OBJECTIVES

Gains in fat mass and lean mass during tuberculosis (TB) treatment may determine functional recovery and survival; yet, data are scarce. We aimed to assess predictors of fat and fat-free mass during 2 months of intensive TB treatment in a cohort in Mwanza, Tanzania.

SUBJECTS/METHODS

Fat and fat-free mass were determined at the start of TB treatment and repeated after 2 months using the deuterium dilution technique. Gains in fat and fat-free mass were determined and predictors assessed using regression analysis.

RESULTS

Data for 116 patients were available at baseline and during follow-up. Of these, 38.8% were females, mean age was 37.3 (s.d. 13.5) years, 69% (81) had sputum-positive TB, 45.7% (53) were HIV infected and 25% (29) were current smokers. The mean weight gain was 3.3 kg (95% confidence interval: 2.7; 3.8), and it did not differ by sex. However, compared with females, males had 1.0 (0.4; 1.6) kg/m(2) lower fat mass but 0.7 (0.2; 1.3) kg/m(2) higher fat-free mass gain. Current smoking was associated with higher fat mass (0.7 kg/m(2), 0.04; 1.4) but lower fat-free mass (-0.5 kg/m(2), -1.2; 0.07) gain. Among HIV-infected patients, antiretroviral therapy (ART) led to a lower fat gain (-1.2 kg/m(2), -2.2; -0.2) but to a higher fat-free mass among sputum-negative (2.9 kg/m(2), 0.8; 5.1) but not sputum-positive patients.

CONCLUSIONS

During intensive phase of TB treatment, sex, smoking and ART were predictors of body composition. Larger studies are needed to further understand predictors of body composition during recovery, to help design interventions to improve treatment outcomes.

Diabetes is associated with lower tuberculosis antigen-specific interferon gamma release in Tanzanian tuberculosis patients and non-tuberculosis controls

BACKGROUND

Diabetes is increasingly common in TB endemic regions and plays a role as a possible risk factor for increased progression from latent TB infection (LTBI) to active TB disease. Although the pathophysiological mechanisms are not fully understood, the immune system is weakened in diabetes patients and therefore the validity of interferon gamma release assays (IGRA) may be compromised. The aim of the present study was to assess the association between diabetes and Mycobacterium tuberculosis (Mtb) antigen-specific interferon gamma (IFN-γ) release in a TB endemic area among culture-confirmed TB patients and non-TB controls.

METHODS

Culture-confirmed pulmonary TB patients (n = 187) and healthy non-TB neighbourhood controls (n = 190) from Mwanza, Tanzania were tested for the presence of circulating T cells recognizing Mtb antigens using an IGRA. The diabetes status of all participants was assessed using a standard oral glucose tolerance test. The impact of diabetes on the performance of the IGRA was estimated using robust linear and logistic regression.

RESULTS

Compared to normal glucose tolerance, diabetes was associated with reduced levels of Mtb-specific IFN-γ. Increasing levels of fasting blood glucose (B - 0.3, 95% confidence interval - 0.6 to - 0.03, p = 0.033) was negatively associated with IFN-γ. Although TB patients had higher specific and lower unspecific mitogen IFN-γ responses compared to non-TB controls, the association between diabetes and IFN-γ did not depend on TB status.

CONCLUSION

Diabetes is associated with lower levels of Mtb antigen-specific IFN-γ, and the validity of IFN- γ tests for LTBI may be questionable in individuals with diabetes.

The role of anthropometric and other predictors for diabetes among urban Tanzanians with tuberculosis

BACKGROUND

As diabetes impairs tuberculosis (TB) treatment outcomes, it is essential to identify diabetes among TB patients. While little is known about predictors of diabetes among healthy individuals in Africa, predictors among TB patients are almost non-existent.

OBJECTIVE

To assess potential predictors for diabetes among newly diagnosed pulmonary TB patients in Tanzania.

METHODS

TB patients were tested for diabetes using an oral glucose tolerance test, demographic information was collected and anthropometric measurements taken. The association between diabetes and possible predictors were examined using logistic regression analyses.

RESULTS

Of 1205 TB patients, 16.4% (n = 197) had diabetes, 9.0% (n = 108) were aged ≥55 years, 3.3% (n = 40) were overweight (body mass index [BMI] ≥ 25 kg/m(2)) and 12.7% (n = 152) severely underweight (BMI < 16 kg/m(2)). Diabetes was most prevalent in the 45-55 year age group, and increasing weight, BMI and waist circumference were associated with diabetes. Severe underweight (BMI < 16 kg/m(2)) among male TB patients (sex-BMI interaction, P = 0.02) was associated with diabetes (OR 2.52, P = 0.004).

CONCLUSION

Diabetes is a common comorbidity among TB patients. Although diabetes was associated with obesity and was more prevalent among the middle-aged, the majority of TB patients with diabetes comorbidity were young and lean. With diabetes as a major risk factor for TB, and with the lack of strong predictors for diabetes, universal diabetes screening should be implemented in the TB programme.

[Research training is inadequate among future medical doctors]

This questionnaire survey investigated interest and activity in pregraduate research among 643 medical students at the Faculty of Health and Medical Sciences at the University of Copenhagen. We find, that although the students show great interest and motivation for research, very few have actual research experience. The students described suboptimal research training, lack of tutoring and facilitation as well as of career counselling. Also, conditions for pregraduate research activities are unequal among the faculties of health sciences in Denmark.

The role of diabetes co-morbidity for tuberculosis treatment outcomes: a prospective cohort study from Mwanza, Tanzania

BACKGROUND

Due to the association between diabetes and pulmonary tuberculosis (TB), diabetes may threaten the control of TB. In a prospective cohort study nested in a nutrition trial, we investigated the role of diabetes on changes in anthropometry, grip strength, and clinical parameters over a five months follow-up period.

METHODS

Among pulmonary TB patients with known diabetes status, we assessed anthropometry and clinical parameters (e.g. haemoglobin) at baseline and after two and five months of TB treatment. A linear mixed-effects model (repeated measurements) was used to investigate the role of diabetes during recovery.

RESULTS

Of 1205 TB patients, the mean (standard deviation) age was 36.6 (13.0) years, 40.9% were females, 48.9% were HIV co-infected, and 16.3% had diabetes. TB patients with diabetes co-morbidity experienced a lower weight gain at two (1.3 kg, CI95% 0.5; 2.0, p = 0.001) and five months (1.0 kg, CI95% 0.3; 1.7, p = 0.007). Similarly, the increase in the level of haemoglobin was lower among TB patients with diabetes co-morbidity after two (Δ 0.6 g/dL, CI95% 0.3; 0.9 p < 0.001) and five months (Δ 0.5 g/dL, CI95% 0.2; 0.9 p = 0.004) of TB treatment, respectively.

CONCLUSION

TB patients initiating TB treatment with diabetes co-morbidity experience delayed recovery of body mass and haemoglobin, which are important for the functional recovery from disease.

Diabetes is a risk factor for pulmonary tuberculosis: a case-control study from Mwanza, Tanzania

BACKGROUND

Diabetes and TB are associated, and diabetes is increasingly common in low-income countries where tuberculosis (TB) is highly endemic. However, the role of diabetes for TB has not been assessed in populations where HIV is prevalent.

METHODS

A case-control study was conducted in an urban population in Tanzania among culture-confirmed pulmonary TB patients and non-TB neighbourhood controls. Participants were tested for diabetes according to WHO guidelines and serum concentrations of acute phase reactants were measured. The association between diabetes and TB, and the role of HIV as an effect modifier, were examined using logistic regression. Since blood glucose levels increase during the acute phase response, we adjusted for elevated serum acute phase reactants.

RESULTS

Among 803 cases and 350 controls the mean (SD) age was 34.8 (11.9) and 33.8 (12.0) years, and the prevalence of diabetes was 16.7% (95% CI: 14.2; 19.4) and 9.4% (6.6; 13.0), respectively. Diabetes was associated with TB (OR 2.2, 95% CI: 1.5; 3.4, p<0.001). However, the association depended on HIV status (interaction, p = 0.01) due to a stronger association among HIV uninfected (OR 4.2, 95% CI: 1.5; 11.6, p = 0.01) compared to HIV infected (OR 0.1, 95% CI: 0.01; 1.8, p = 0.13) after adjusting for age, sex, demographic factors and elevated serum acute phase reactants.

CONCLUSION

Diabetes is a risk factor for TB in HIV uninfected, whereas the association in HIV infected patients needs further study. The increasing diabetes prevalence may be a threat to TB control.