Ideal Cardiovascular Health Index and Its Determinants in a Rural South African Population

Background: The ideal cardiovascular health index (CVHI) is a measure to summarize cardiovascular (CV) health, and includes smoking, body-mass index, physical activity, blood pressure, glucose, total cholesterol, and diet. Objective: This study aimed to assess CV health using the CVHI and determinants on CV health in a rural African population, and correlate carotid intima-media thickness (CIMT), a surrogate marker for atherosclerosis, with CVHI. Methods: A cross-sectional analysis was performed on baseline data of the Ndlovu Cohort Study, located in rural South Africa. CVHI score (CVHIs) was calculated by the sum of favourable CVHI factors (range 0 to 7). Logistic regression was performed to examine the association of age, sex, HIV-status, education level, employment status, and income with good CV health (5-7 favourable health factors). Mean CIMT was displayed by poor, intermediate and good CV health. Results: The study included 1927 participants with a mean age of 38.7 years (SD ± 12.8). Of the factors contributing to the CVHI, glucose and total cholesterol scored best; diet least good. Average CVHIs for the population was 4.4 (SD ± 1.2) and 53% of the population had a good CV health. Determinants associated with good CV health were younger age, higher educational attainment, and HIV positivity. CVHIs showed good agreement with CIMT. Conclusion: CVHIs showed that more than half of the participants had a good CV health. Agreement between CVHIs and CIMT indicates potential use of CVHIs as a surrogate marker for CV risk. The study highlights the importance of education for health promotion; good CV health in HIV-positive participants may in part be attributed to more frequent health care contact and provision of chronic disease care. Highlights: Good cardiovascular health (CVH) was observed in 53% of the study population.In global comparison, rural African study participants showed a good CVH score.HIV positivity was associated with a good CVH score.CVH score showed good agreement with carotid intima-media thickness

Comparative performance of cardiovascular risk prediction models in people living with HIV

Background: Current cardiovascular risk assessment in people living with HIV is based on general risk assessment tools; however, whether these tools can be applied in sub-Saharan African populations has been questioned.Objectives: The study aimed to assess cardiovascular risk classification of common cardiovascular disease (CVD) risk prediction models compared to the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) 2010 and 2016 models in people living with HIV.Method: Cardiovascular disease risk was estimated by Framingham Cardiovascular and Heart Disease (FHS-CVD, FHS-CHD), Atherosclerotic Cardiovascular Disease (ASCVD) and D:A:D 2010 and 2016 risk prediction models for HIV-infected participants of the Ndlovu Cohort Study, Limpopo, rural South Africa. Participants were classified to be at low ( 20%) of CVD within 10 years for general CVD and five years for D:A:D models. Kappa statistics were used to determine agreement between CVD risk prediction models. Subgroup analysis was performed according to age.Results: The analysis comprised 735 HIV-infected individuals, predominantly women (56.7%), average age 43.9 (8.8) years. The median predicted CVD risk for D:A:D 2010 and FHS-CVD was 4% and for ASCVD and FHS-CHD models, 3%. For the D:A:D 2016 risk prediction model, the figure was 5%. High 10-year CVD risk was predicted for 2.9%, 0.5%, 0.7%, 3.1% and 6.6% of the study participants by FHS-CVD, FHS-CHD, ASCVD, and D:A:D 2010 and 2016. Kappa statistics ranged from 0.34 for ASCVD to 0.60 for FHS-CVD as compared to the D:A:D 2010 risk prediction model.Conclusion: Overall, predicted CVD risk is low in this population. Compared to D:A:D 2010, CVD risk estimated by the FHS-CVD model showed similar overall results for risk classification. With the exception of the D:A:D model, all other risk prediction models classified fewer people to be at high estimated CVD risk. Prospective studies are needed to develop and validate CVD risk algorithms in people living with HIV in sub-Saharan Africa.</div

Chronotype Genetic Variant in PER2 is Associated with Intrinsic Circadian Period in Humans

This is the final version. Available on open access from Nature Research via the DOI in this recordData Availability: The data that support the findings of this study from the UK BioBank will be made available at https://sleepgenetics.org and the underlying genotype and phenotype data are available through application to the UK Biobank. Other phenotype data are available on request, due to privacy or other restrictions, through co-corresponding author Dr. Scheer ([email protected]).The PERIOD2 (PER2) gene is a core molecular component of the circadian clock and plays an important role in the generation and maintenance of daily rhythms. rs35333999, a missense variant of PER2 common in European populations, has been shown to associate with later chronotype. Chronotype relates to the timing of biological and behavioral activities, including when we sleep, eat, and exercise, and later chronotype is associated with longer intrinsic circadian period (cycle length), a fundamental property of the circadian system. Thus, we tested whether this PER2 variant was associated with circadian period and found significant associations with longer intrinsic circadian period as measured under forced desynchrony protocols, the ‘gold standard’ for intrinsic circadian period assessment. Minor allele (T) carriers exhibited significantly longer circadian periods when determinations were based on either core body temperature or plasma melatonin measurements, as compared to non-carriers (by 12 and 11 min, respectively; accounting for ~7% of inter-individual variance). These findings provide a possible underlying biological mechanism for inter-individual differences in chronotype, and support the central role of PER2 in the human circadian timing system.European CommissionWellcome TrustMedical Research Council (MRC

Cardiovascular disease risk and its determinants in people living with HIV across different settings in South Africa

OBJECTIVES: Socio-economic factors and lifestyle are known to differ across geographies and populations, which may result in distinct risk profiles for cardiovascular disease (CVD). This study assessed carotid intima-media thickness (CIMT), a proxy for CVD, and its determinants in two groups of people living with HIV (PLHIV) in two different settings in South Africa. METHODS: A cross-sectional analysis was conducted comparing data from the Ndlovu Cohort Study in the Limpopo Province (group 1) and from three clinical trials in Johannesburg (group 2). The association between demographics, conventional CVD risk factors, HIV-related factors and CIMT in groups 1 and 2 was analysed with two separate multivariable linear regression models. RESULTS: Group 1 consisted of 826 participants (mean age 42.2 years) and mean (± standard deviation) CIMT was 0.626 ± 0.128 mm. In this group, sex, age, body mass index (BMI), cholesterol, glucose and antiretroviral therapy (ART) duration (β = 0.011 mm per 5 years; P = 0.02) were associated with higher CIMT. There were positive interactions between age and ART duration and age and cholesterol. Group 2 consisted of 382 participants (mean age 39.5 years) and mean (± standard deviation) CIMT was 0.560 ± 0.092 mm. In this group, only sex, education level, BMI and cholesterol were associated with higher CIMT, albeit with weaker associations than in group 1. CONCLUSIONS: Conventional CVD risk factors were the main drivers of CIMT. The impact of some of these risk factors appeared to increase with age. Differences in sample size, age and viral suppression might explain why an effect of ART was observed in group 1 but not in group 2

Impact of Common Diabetes Risk Variant in MTNR1B on Sleep, Circadian, and Melatonin Physiology

The risk of type 2 diabetes (T2D) is increased by abnormalities in sleep quantity and quality, circadian alignment, and melatonin regulation. A common genetic variant in a receptor for the circadian-regulated hormone melatonin (MTNR1B) is associated with increased fasting blood glucose and risk of T2D, but whether sleep or circadian disruption mediates this risk is unknown. We aimed to test if MTNR1B diabetes risk variant rs10830963 associates with measures of sleep or circadian physiology in intensive inlaboratory protocols (n = 58–96) or cross-sectional studies with sleep quantity and quality and timing measures from self-report (n = 4,307–10,332), actigraphy (n = 1,513), or polysomnography (n = 3,021). In the in-laboratory studies, we found a significant association with a substantially longer duration of elevated melatonin levels (41 min) and delayed circadian phase of dim-light melatonin offset (1.37 h), partially mediated through delayed offset of melatonin synthesis. Furthermore, increased T2D risk in MTNR1B risk allele carriers was more pronounced in early risers versus late risers as determined by 7 days of actigraphy. Our results provide the surprising insight that the MTNR1B risk allele influences dynamics of melatonin secretion, generating a novel hypothesis that the MTNR1B risk allele may extend the duration of endogenous melatonin production later into the morning and that early waking may magnify the diabetes risk conferred by the risk allele