The Double Burden.

One third of the world's population is latently infected with Mycobacterium tuberculosis, and with the lifestyle changes succeeding the on-going urbanization, populations already burdened by tuberculosis are experiencing a dramatic increase in chronic diseases, with diabetes being a serious challenge. Tuberculosis and diabetes are not only becoming co-existing diseases. In fact, the diseases interact, and there is evidence to suggest that especially diabetes disease increases the susceptibility for developing active tuberculosis disease. Furthermore, it is plausible that tuberculosis leads to, either transient or permanent, impairment of the glucose metabolism, which ultimately will turn into diabetes. A number of studies from the Americas, Europe, Asia, and, most lately, from sub-Saharan Africa have reported strong association between tuberculosis and diabetes; on average, the estimated risk of active tuberculosis is thrice as high among people with diabetes. The study from sub-Saharan Africa was conducted in Tanzania and is the basis of this thesis. Based on available evidence on the association between tuberculosis and diabetes, the primary aim of the study was to assess the role of diabetes for tuberculosis risk, manifestations, treatment outcomes and survival in a Tanzanian population of tuberculosis patients and non-tuberculosis neighbourhood controls. The study was conducted in Mwanza City in northern Tanzania, with a population exceeding half a million inhabitants, with tuberculosis and HIV being common infections in the region, but with little knowledge about the prevalence of diabetes. We recruited newly diagnosed pulmonary tuberculosis patients from spring 2006 and continuously till the fall 2009, with all participating in a nutritional intervention running in parallel with the medical tuberculosis treatment. All participants underwent diabetes and HIV testing as well as a series of measurements such as anthropometric, clinical and paraclinical parameters. The population was followed up during treatment (2 and 5 months) to assess treatment outcome as well as after one year to assess their survival status. Based on data from 1,250 tuberculosis patients and 350 neighbourhood controls, we found that 38 and 21%, respectively, had impaired glycaemia, and that the prevalence of diabetes was 17 and 9% among tuberculosis patients and controls, respectively. This difference in prevalence between patients and controls was equivalent to an adjusted odds ratio of more than four, indicating a strong association between tuberculosis and diabetes. Furthermore, we found that diabetes was associated with tuberculosis among both participants with or without HIV co-infection. Despite the strong association, diabetes had only moderate clinical implications when the tuberculosis patients initiated the tuberculosis treatment; the patients with diabetes co-morbidity had a minor elevation in the immune response and more frequently reported to have fever. Furthermore, diabetes did not seem to delay time to sputum conversion during treatment. Nevertheless, diabetes co-morbidity led to impaired treatment outcome with slower recovery of weight and haemoglobin and a more than four times higher mortality rate within the initial phase of tuberculosis treatment. In conclusion, in the African region, the double burden of tuberculosis and diabetes is becoming a major health problem. Although the tuberculosis incidence has stabilized during the last decade, the increasing incidence of diabetes will possibly interfere with tuberculosis control and may, consequently, make the tuberculosis incidence increase again. Future research strategies should focus on enhanced diagnostic tools to identify tuberculosis patients with diabetes co-morbidity, and on the role of disease-disease, drug-disease and drug-drug interactions between tuberculosis and diabetes diseases and treatments

The Role of Diabetes Co-Morbidity for Tuberculosis Treatment Outcomes: A Prospective Cohort Study from Mwanza, Tanzania.

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. 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. 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. 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

Vitamin D Status among Pulmonary TB Patients and Non-TB Controls: A Cross-Sectional Study from Mwanza, Tanzania.

Little is known about vitamin D status in low-income populations burdened with infectious diseases. Hence, there is a need for data on correlates of serum 25-hydroxy vitamin D (S-25(OH)D) and its validity during infections. To assess the role of pulmonary TB (PTB) and HIV as correlates of S-25(OH)D. Age-sex-matched cross-sectional study among PTB patients and non-TB controls. PTB patients were categorized as sputum negative (PTB-) and positive (PTB+) by culture. Non-TB controls were randomly selected among age-sex-matched neighbours to PTB+ patients. Height, weight, arm circumference and triceps skinfold were measured, and body mass index (BMI), arm fat (AFA) and muscle area (AMA) computed. HIV status, and S-25(OH)D, C-reactive protein (S-CRP) and α1-acid glycoprotein (S-AGP) were determined. Linear regression analysis with controls and PTB patients combined was used to identify correlates of S-25(OH)D. S-25(OH)D data were available on 97.8% (1570) of 1605 participants. Mean (SD) S-25(OH)D was 84.4 (25.6) nmol/L with 39.6% <75 nmol/L among 347 non-TB controls. Time of recruitment, sex, PTB and HIV, and elevated S-AGP were correlates of S-25(OH)D. S-25(OH)D was 24.8 (95% CI 18.6;30.9) nmol/L higher in PTB compared to controls among females, but only 9.8 (95% CI:4.5;15.2) nmol/L among males (interaction p<0.0001). Females had 13.8 (95% CI:8.2;21.9) nmol/L lower S-25(OH)D than males, and HIV infected individuals had 8.5 (95% CI:4.9;12.1) higher S-25(OH)D compared to uninfected. Elevated S-AGP was a positive correlate of S-25(OH)D. Low BMI was associated with S-25(OH)D, but not with infections or S-AGP in the model. While S-25(OH)D may decline transiently during a mild acute phase response, it may increase if the acute phase response leads to loss of fat. The validity of S-25(OH)D as a marker of vitamin D status may be affected by infections