Diet and exercise advice lowers diabetes risk in people with HIV

Rates of diabetes are higher in people living with HIV than in the general population, but individualised lifestyle advice from a dietitian led to clinically and statistically significant reductions in glucose, weight and other risk factors in a small, single-arm study in London, reported in Diabetic Medicine.

“Significant barriers to diet and lifestyle behaviour change exist within HIV, including stigma, isolation and body image challenges, which should be taken into consideration when designing diabetes prevention interventions,” comment Alastair Duncan of Guy’s and St Thomas’ Hospital and colleagues. Their mixed-methods study provides qualitative data giving insight into factors that motivate individuals to change their lifestyle or that prevent behaviour change.

Previous studies of lifestyle interventions with people with HIV have mostly focused on cardiovascular risk and have not had an impact on diabetes risk.

The intervention evaluated here involved six one-to-one monthly visits, each lasting 30 minutes, in which a dietitian provided individualised advice on making lifestyle changes. The intervention aimed to achieve moderate weight loss through energy restriction and increased physical activity, alongside reductions in saturated fat, sugar and salt, and increases in consumption of wholegrains, fruit and vegetables. These goals were informed by two diabetes prevention trials conducted in the general population.

Monthly targets to achieve goals were agreed jointly by the dietitian and the participant. Motivational interviewing and cognitive behaviour therapy techniques, such as goal-setting and self-monitoring, were used. Targets were individualised: for example, dietary advice was tailored to ethnicity, food habits, socioeconomic status, lifestyle patterns, access to food, cooking ability, and medical issues.

Twenty-eight people living with HIV completed the intervention. As an inclusion criteria, all had levels of fasting glucose (6.0 - 6.9 mmol/l) indicating ‘pre-diabetes’ – an increased risk of developing diabetes. A level above this would indicate diabetes. Their mean age was 54, three-quarters were men and they were ethnically diverse. 

At baseline, mean body mass index was 30.5 (levels above 30 indicate obesity), 57% had hypertension, 79% metabolic syndrome, 61% hepatic steatosis and 4% cardiovascular disease.

Participants had been taking HIV treatment for an average of ten years and just under half had previously taken antiretrovirals that may contribute to diabetes risk (zidovudine, stavudine, didanosine, indinavir, lopinavir).

Of the ten lifestyle goals which were proposed, participants achieved a median of five goals. The most frequently achieved goal, reducing sodium intake to < 2.5 g per day, was attained by 82% of participants, 61% achieved restriction of added sugar to < 25g per day, 57% achieved 10,000 steps per day, and 57% were able to restrict saturated fat to < 10% of total energy intake.

However, only 22% were able to achieve the goal of a 7% weight loss and 14% achieved the goal of increasing monounsaturated fat intake to > 15% of total energy intake. Nonetheless, some of these goals were partially achieved.

Comparing results at baseline and at the end of the six month intervention, the programme significantly reduced:

• fasting glucose (down 7.9%, from 6.3 to 5.8 mmol/l)
• glucose incremental area under the curve in a meal tolerance test (down 17.6%, from 255 to 210 mmol/l x min)
• fasting insulin (down 22.7%, from 100.1 to 77.1 pmol/l)
• insulin incremental area under the curve in a meal tolerance test (down 31.4%, from 1870 to 1283 pmol/l x min)
• weight (down 4.6%, from 88.8 to 84.7kg)
• waist circumference (down 6.2%, from 107.1 to 100.5cm)
• systolic blood pressure (down 7.4%, from 135 to 125 mmHg)
• triglycerides (down 36.7%, from 2.07 to 1.31 mmol/l).

The researchers note that these reductions are greater than the reductions typically seen in ‘real world’ studies with largely HIV-negative participants, such as fasting glucose reduced by 0.09 mmol/l and weight reduced by 2.5kg. In general population studies, these changes are associated with a 29% reduced incidence of diabetes.

Qualitative data

Semi-structured interviews were conducted with 15 of the 28 participants, and also with eight individuals who declined to take part or dropped out. Participants generally found the intervention acceptable, particularly appreciating improved knowledge and skills, motivational interviewing, stepwise goal-setting with tools such as pedometers, and monthly support.

They perceived the intervention to have potential to impact a wide range of health concerns:

“It doesn't just get rid of belly fat, it is good for the heart and for one mentally as well” (60-year-old man).

Those able to make behaviour changes were often motivated by having a sense of control regarding the prevention of diabetes. They had more access to social support than those who did not achieve goals.

Those who declined to take part in the intervention described monthly appointments as burdensome. The interviews also identified some barriers to behaviour change that are specific to HIV. Firstly, body shape changes associated with lipodystrophy affected some participants’ body image and comfort with exercise:

“My stomach. Every time I go to the gym people think I'm pregnant because of the lipodystrophy” (55-year-old woman).

Interviewees of all ethnicities worried that weight loss might lead to disclosure of HIV status or be associated with HIV‐related illness:

“If I lose weight… the first thing they will point at, that one has got AIDS. Because of the weight you have lost” (49-year-old woman).

Participants of African origin described being overweight as culturally desirable. A loss of cultural identity could be a significant barrier to weight reduction:

“I said, “Oh look how big I am”. They said, “Oh no, you're not big, that is the good right thing”….. They said, “no, no, no, don't lose weight”” (51-year-old woman).

This was echoed among gay men who self‐identified as ‘bears’ (a sub-section of gay men who reject idealised lean muscularity, and tend to be bearded, hairier and heavier than other gay men).

However, some other gay men felt a cultural pressure to achieve a lean physical aesthetic:

“Well, I looked at myself side on in the mirror and I thought would you sleep with you and I thought no I wouldn’t” (60-year-old man).

Some interviewees attributed their increased risk to HIV medications and considered prevention measures futile. These individuals tended to either not achieve intervention goals or to decline participation in the intervention.

“As you get older and you're on these [HIV] drugs, this [diabetes] is just going to happen. There's nothing you can do. You can try to be healthy but you're not going to avoid it” (46-year-old man).

“I have a problem because of the HIV medication I'm taking because I know it makes me put on weight” (40-year-old man).

But for interviewees who achieved more goals, a desire to avoid adding to pill burden or disease burden motivated behaviour change.

“To have to start diabetes medicines as well, on top of the HIV ones, I thought, that is going to be very hard” (48-year-old woman).

Some believed that diabetes prevention was achievable and less burdensome than living with HIV:

“Diabetes is a disease but I know it can be easily tackled with food without taking any medicine. But HIV is not like that” (71-year-old man).

The researchers conclude: “We have demonstrated the beneficial effects of a lifestyle intervention in mitigating the increased risk of Type 2 diabetes associated with HIV. Future interventions should be designed to further reduce the unique barriers that prevent successful outcomes in this cohort.”