Associations Among BMI, Waist Circumference, Neuropsychological Performance in Women With HIV Appear Unclear

The associations of body mass index (BMI) and waist circumference (WC) with neuropsychological performance (NP) among women living with HIV (WLWH) vs women without HIV (WWOH) appeared mixed, according to a study published in Frontiers in Endocrinology.

The researchers noted that previous studies suggested higher levels of either BMI or WC increase the risk of subsequent later-life cognitive decline, vascular cognitive impairments and dementias, and late-onset Alzheimer disease. One such study was conducted among men living with HIV (MLWH) and without HIV (MWOH).

This study established that a higher BMI was inversely associated with motor function and attention/working memory in MWOH. Also, WC was inversely associated with motor performance decline in MWOH and MLWH. Additionally, MLWH with obesity showed a decline in motor function across 10-year NP trajectory analyses, whereas MWOH with obesity had a greater decline in learning, memory performance, and motor function.

Because of these findings, the researchers looked to discover if similar relationships would be observed in WLWH and WWOH. For these analyses, they examined multivariable-adjusted associations of WC and BMI with NP cross-sectionally and prospectively over about 10 years within WLWH and WWOH.

“Our primary hypothesis was that higher adult BMI and WC would be associated with poorer NP, and this association would be more pronounced among WLWH using both cross-sectional and longitudinal approaches,” the authors wrote.

The researchers calculated BMI as kg/m², categorizing it using traditional guidelines, with 25.0 to 29.9 kg/m² being overweight and 30 kg/m² or greater being obese. They also explained that central obesity was clinically measured with WC in cm; researchers either categorized participants’ WCs as low risk (<88 cm or <38 inches)or high risk (≥88 cm or ≥35 inches). Additionally, various comprehensive NP assessments were administered, which measured the participants’ learning, memory, executive function, processing speed, motor function, and attention and working memory.

To create their study population, the Women’s Interagency HIV Study (WIHS) recruited WLWH and a similar group of WWOH. Eligible participants were 40 years or older, had no documented dementia, had clinically measured BMI and WC, and had their full NP battery completed at 2 or more visits. Also, WLWH could only be included if they took antiretroviral therapies and achieved virologic suppression. Consequently, the researchers included 432 WLWH and 367 WWOH in the study population.

Of the participants, the median age was 45 years, ranging between 41 and 56, and the mean (SD) follow-up length was 8.0 (1.5) years. The researchers noted that 28% of WLWH were overweight, 45% were obese, and 69% had a high-risk WC; they participated in a median (IQR) of 4 (3-4) NP study visits, totaling 1641 visits. In comparison, 26% of WWOH were overweight, 56% were obese, and 75% had a high-risk WC. WWOH also had a median (IQR) of 4 (3-4) NP study visits, totaling 1403 visits.

Throughout the study, the WIHS collected survey and clinical data, as well as biospecimens, in the same manner at all research sites. The researchers explained that “WIHS data and specimen collection methods were protocol-driven and conducted by dedicated, trained study personnel,” which allowed for standardized data collection and quality assurance.

From this study, associations of BMI and WC with NP decline were not as strong and less consistent than in the previous all-male study. In the current study, researchers observed cross-sectional associations among WLWH between total and central obesity with poorer executive and motor function, respectively. Longitudinally, the researchers found the associations between baseline higher total adiposity and NP were mixed for memory among WWOH. On the other hand, increasing WC was associated with decreasing executive function, motor function, and processing speed. Additionally, an at-risk WC was associated with improved memory performance over time within WWOH.

The researchers attributed the different results between the 2 studies to dissimilar populations. They highlighted that the populations differed in biological sex, baseline BMI, median baseline age, race, and more.

Along with their unexpected findings, the researchers identified various limitations to their study, one being that their study population included only participants 40 years or older, the oldest being 56 years. Consequently, they hypothesized that this “may have minimized robust associations more commonly observed in older adults.”

Because of this, the researchers noted that further research could be aided by extending their assessment timeline beyond 10 years.

“Longer follow-up to older ages and additional measures of NP will clarify trajectories and allow understanding of the temporal nuances of this association,” the authors concluded.

Reference

Vásquez E, Kuniholm MH, Appleton AA, et al. Midlife body mass index, central adiposity and neuropsychological performance over 10 years in women living with and without HIV. Front Endocrinol (Lausanne). 2023;14:1108313. doi:10.3389/fendo.2023.1108313