Longitudinal trends in glycated hemoglobin among individuals with latent TB infection in Addis Ababa, Ethiopia Open Access

Kisho, Amanuel (Spring 2024)

Permanent URL: https://etd.library.emory.edu/concern/etds/wd375x640?locale=en
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Abstract

Introduction: Diabetes increases the risk of TB disease, but whether latent tuberculosis infection (LTBI) may increase the risk of developing diabetes following exposure to Mycobacterium tuberculosis (Mtb) is unknown. We assessed the relationship between body mass index (BMI) and change in glycated hemoglobin (HbA1c) in close contacts of persons who had active pulmonary tuberculosis in Addis Ababa, Ethiopia.

Methods: In this cohort study, 235 household contacts (HHCs) with LTBI were followed from 2016–2021. Glycated hemoglobin was measured at enrollment and every 6 months over 2 years of follow-up. BMI was classified as underweight (< 18.5 Kg/m2), normal-weight (18.5 – 24.9 Kg/m2), and overweight or obese (³ 25 Kg/m2). The 6-month change in HbA1c (comparing HbA1c measured at baseline and after 6-months’ follow-up) was defined as an increase when a participant’s HbA1c level increased by 0.3 percentage points or more, no change when the change was 0 to 0.3 HbA1c percentage points, or a decrease when a participant’s level decreased by 0.3 percentage points or more. The association between diabetes status and TB antigen response with change in HbA1c was also assessed in supplementary analysis. We used multivariable linear and ordinal logistic regression to determine the association between BMI and 6-month change in HbA1c.

Result: The median BMI of participants who had an increase and decrease in 6-month change in HbA1c was 22.8 (IQR: 19.0-29.4) and 20.8 (IQR: 19.0-23.9), respectively, compared to a median BMI of 21.4 (IQR: 18.8-24.5) in participants who had no change in HbA1c. The adjusted linear regression model estimated a significant increase in HbA1c for both overweight (B = 0.1, 95% CI: -0.05–0.2) and obese participants (B = 0.4, 95% CI: 0.1–0.6) and adjusted ordinal logistic regression estimated higher odds of having an increase in change in HbA1c both in overweight (OR=1.6; 95% CI: 0.6-4.5) and obese participants (OR=11.5; 95% CI: 2.8–47.5) compared to those with normal-weight BMI.

Conclusion: Overweight and obese individuals with LTBI may be more likely to develop increases in HbA1c shortly after exposure to Mtb. Additional studies are needed to understand immune mechanisms that may impact abnormal glycemic control in the context of TB.

Table of Contents

Introduction 8

Methods 11

Study Design and Study Population 11

Study outcomes 12

Additional study measures 12

Statistical analysis 13

Ethical considerations 14

Results 14

Sociodemographic characteristics 14

Distribution of body mass index, diabetes status, and TB antigen response by characteristics of the study participants 15

Change in glycated hemoglobin during follow-up 16

Association between BMI and the 6-month change in HbA1c 16

Associations between diabetes status and TB antigen response with 6-month change in HbA1c. 17

Discussion 18

Strength and Limitations 20

Conclusion 20

Policy implications 21

Figures and Tables 22

Supplementary materials 35

References 44

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