Physical activity levels, cardiorespiratory fitness and diabetes mellitus among people living with hiv and hiv-uninfected adults in Tanzania

Introduction
Studies in high-income countries suggest that physical inactivity and poor cardiorespiratory fitness may increase the risk of developing diabetes in the adult population. However, there are limited studies specifically among people living with HIV (PLWH) on levels of physical activity and poor cardiorespiratory fitness and the extent to which these may contribute to the development of diabetes in Sub-saharan Africa (SSA). In addition, most studies have used subjective measures to assess physical activity levels and have not explored social–cultural influences on physical activity.
ObjectivesThe overall objective of the study was to assess physical activity and cardiorespiratory fitness levels in the adult population including, PLWH in Tanzania, and perceptions, facilitators or barriers of physical activity, change in levels of physical activity and capacity during antiretroviral therapy (ART) and the association of physical activity and cardiorespiratory fitness with diabetes. Study-specific objectives were 1) to assess levels and correlates of physical activity and capacity among PLWH compared to HIV-uninfected individuals; 2) to explore perceptions, facilitators, and barriers of physical activity among PLWH; 3) to assess change in physical activity and capacity during the first year of ART among PLWH; 4) to assess the association of physical activity, cardiorespiratory fitness and beta–cell dysfunction, insulin resistance, and diabetes among adults with and without HIV in Mwanza, Tanzania.
MethodsTo address the stated objectives, four sub-studies were conducted in Mwanza, Tanzania. Study 1 titled: "Levels and Correlates Physical Activity and Capacity among PLWH compared to HIVuninfected individuals" addressing objective 1 was a cross-sectional study conducted among PLWH ART-naive and HIV-uninfected individuals frequency-matched for age and sex. Data on socio-demographic, anthropometric measurements, CD4 counts, haemoglobin level, and Creactive protein were collected. Using a combined heart rate and accelerometer monitor (Actiheart), physical activity energy expenditure (PAEE) was assessed as a measure of physical activity and sleeping heart rate (SHR) was assessed as a measure of physical capacity. Grip strength also as a measure of physical capacity was assessed using a handgrip dynamometer. Multivariable linear regression was used to assess the correlates of physical activity and capacity.
Study 2, titled; ―Perceptions, Facilitators and Barriers of Physical Activity among PLWH‖, addressing objective 2, was a qualitative study, where sixteen in-depth interviews and three focus groups with nine participants in each were conducted. The interviews and focus groups were audio recorded, transcribed, and translated into English. The social-ecological model was used during the coding and interpretation of the results. Transcripts were discussed, coded, and analyzed using deductive content analysis.
Study 3 titled; ―Changes in Physical Activity and Capacity during the First Year of Antiretroviral therapy (ART) among PLWH in Tanzania‖, was a prospective cohort study addressing objective 3. Data on socio-demography, anthropometry, body composition, haemoglobin, CD4 count, Creactive protein (CRP), and diabetes were collected before participants started ART. Linear regression was used to assess associations of these variables with changes in physical activity energy expenditure (PAEE), moderate-vigorous intensity physical activity, sedentary percent time, acceleration, sleeping heart rate (SHR), and grip strength from baseline until one year of ART.

Study 4, addressing objective 4, was a cross-sectional study conducted among ART-naïve PLWH and HIV-uninfected individuals to assess the association of physical activity, cardiorespiratory fitness, beta-cell dysfunction, insulin resistance, and diabetes among adults. Data on socio-demography, anthropometry, and C-reactive protein were collected. Glucose and insulin data were collected during an oral glucose tolerance test and were used to assess beta-cell dysfunction (defined as insulinogenic index <0.71 (mU/L)/(mmol/L), HOMA-β index <38.3 (mU/L)/(mmol/L), and overall insulin release index <33.3 (mU/L)/(mmol/L)), oral disposition index <0.16 (mU/L)/(mg/dL)(mU/L)-1, insulin resistance (HOMA-IR index >1.9 (mU/L)/(mmol/L) and Matsuda index <7.2 (mU/L)/(mmol/L), prediabetes and diabetes which were the dependent variables. Physical activity energy expenditure (PAEE), sleeping heart rate (SHR), and maximum uptake of oxygen during exercise (VO2 max) were the independent variables and were assessed using a combined heart rate and accelerometer monitor. Logistic regressions were used to assess the associations.'
ResultsIn study 1, 272 PLWH ART-naive and 119 HIV-uninfected individuals, a mean age 39 years, and 60% of women were included. Compared to HIV-uninfected individuals, PLWH had lower physical activity, PAEE (-7.3 kj/kg/day, 95%CI: -11.2, -3.3), elevated SHR (7.7 beats/min, 95%CI: 10.1, 5.3) and reduced grip strength (-4.7 kg, 95%CI: -6.8, -2.8) implicating poor cardiorespiratory fitness and physical capacity. In PLWH, low BMI, moderate-severe anaemia, low CD4 counts, and high CRP were associated with lower physical activity and capacity. In HIV-uninfected individuals, abdominal obesity and moderate-severe anaemia were significantly associated with lower physical activity and capacity.
In study 2, 43 PLWH aged 23-61 years were included. The findings showed that most PLWH perceived physical activity as beneficial to their health. However, their perceptions of physical activity were rooted within existing gender stereotypes and roles in the community. Running and playing football were perceived as activities for men while household chores activities were for women. Further, men were perceived to do more physical activity than women. For women, household chores and income-generating activities were perceived as sufficient physical activity. Social support and engagement of family members and friends in physical activity were reported as the main facilitators of physical activity. Reported barriers to physical activity among PLWH were lack of time, money, availability of physical activity facilities and social support groups, and poor information sharing on physical activity from health care providers in HIV clinics. HIV infection was not perceived by PLWH as a barrier to doing physical activity but most family members did not support them to participate in physical activity, fearing that it might worsen their condition.
In study 3, 65 PLWH were recruited. Their mean age was 41 (±11.9) years and 60% (n=39) were females. During the first year on ART, PLWH increased PAEE (8.4 kj/kg/day, 95%CI: 4.0, 12.7), time in moderate-vigorous physical activity (1 %/h/day 95%CI: 0.03, 2), acceleration (0.03 m/s, 95%CI: 0.01, 0.05), and grip strength (5.0 kg, 95%CI: 3.6, 6.4) and reduced time in sedentary activity (-4% /h/day, 95%CI: -6, -2), but there was no change in SHR. Lower baseline CRP was associated with a greater increase in grip strength (2.91 kg, 95%CI: 1.00, 4.82) and higher baseline fat-free mass and lower haemoglobin levels with less increase in grip strength (0.42 kg, 95%CI: -0.64, -0.20) and (-1.01 kg, 95%CI: -1.88, -0.14), respectively.
In study 4, 391 participants were recruited. 272 of them were PLWH ART-naive and 119 were HIV-uninfected. The mean age was 39 (±10.5) years and 60% (n=235) were females. Compared to the lower tertile, the middle tertile of PAEE was associated with lower odds of the abnormal insulinogenic index (OR=0.48, 95%CI: 0.27, 0.82). A 5 kj/kg/day increment of PAEE was associated with lower odds of abnormal HOMA-IR (OR=0.91, 95%CI: 0.84, 0.98), and reduced risk of pre-diabetes (RRR=0.98, 95%CI: 0.96, 0.99) and diabetes (RRR=0.92, 95%CI: 0.88, 0.96). An increment of 5 beats per minute of SHR was associated with a higher risk of diabetes (RRR=1.06, 95%CI: 1.01, 1.11). An increase of 5 mLO2/kg/min of VO2 max was associated with a lower risk of pre-diabetes (RRR=0.91, 95%CI: 0.86, 0.97), but not diabetes. HIV status did not modify any of these associations (interaction, p>0.05).
ConclusionPLWH ART-naive participants had lower levels of physical activity and capacity compared to HIV-uninfected individuals and correlates of physical activity and capacity differed by HIV status. Obesity and anaemia were high and among the factors associated with reduced physical activity among HIV-uninfected individuals. Levels of physical activity and capacity among PLWH improved after initiating ART and at such that by the end of one year of ART, there was no difference in these measurements between PLWH and HIV-uninfected individuals. PLWH perceived that men do more physical activity than women and women perceive house chores are physical activity and recreational sports are exercise and are for men. PLWH specifically women perceived house chores and income-generating activities are sufficient physical activity. Factors that facilitated physical activity practices among PLWH were encouragement and physical support from family members and friends while the main barriers were lack of time and physical activity facilities, support groups, and physical activity promotional messages from health care professionals to emphasize the importance of physical activity. Lastly, we found that adequate physical activity and high cardiorespiratory fitness were associated with reduced risk of beta-cell dysfunction, insulin resistance, and, diabetes.