Cardiovascular mortality - Comparing risk factor associations within couples and in the total population - The HUNT Study

Assortative mating and within-spouse pair comparisons

Spousal comparisons have been proposed as a design that can both reduce confounding and estimate effects of the shared adulthood environment. However, assortative mating, the process by which individuals select phenotypically (dis)similar mates, could distort associations when comparing spouses. We evaluated the use of spousal comparisons, as in the within-spouse pair (WSP) model, for aetiological research such as genetic association studies. We demonstrated that the WSP model can reduce confounding but may be susceptible to collider bias arising from conditioning on assorted spouse pairs. Analyses using UK Biobank spouse pairs found that WSP genetic association estimates were smaller than estimates from random pairs for height, educational attainment, and BMI variants. Within-sibling pair estimates, robust to demographic and parental effects, were also smaller than random pair estimates for height and educational attainment, but not for BMI. WSP models, like other within-family models, may reduce confounding from demographic factors in genetic association estimates, and so could be useful for triangulating evidence across study designs to assess the robustness of findings. However, WSP estimates should be interpreted with caution due to potential collider bias.

Community pharmacies offer a potential high-yield and convenient arena for total cholesterol and CVD risk screening

Background

Moderately elevated blood total cholesterol (TC), blood glucose (BG) and blood pressure (BP) are rarely symptomatic and as such many individuals remain untreated. We studied the yield of an in-pharmacy screening for identifying undetected high TC and strategies to reach those with absence of prior measurement of TC, BG and BP.

Methods

A cross-sectional TC screening study with complementary TC measurements and self-administered questionnaire was conducted for 1 week in each of 2012 and 2014 in 148 and 149 BootsTM Norge AS community pharmacies nationwide in Norway.

Results

Non-medicated adults (n = 21 090) with mean age 54.5 ± 16.0 were included. The study population resembled the Norwegian population in regards to body mass index, educational level, smokers and physical inactivity level, but with an overrepresentation of middle-aged women. Of 20 743 with available data, 11% (n = 2337) were unaware of their high TC ≥7.0 mmol/L, and an additional 8% were unaware of TC ≥6.2 mmol/L. More than 40% of the study sample had not measured TC or BG before. In order for future screenings to reach those who are less likely to have previously measured TC and BG, our results suggest that young, low-educated, overweight men and women should be targeted for TC measurement, whereas normal weigh men in all ages should be targeted for BG measurement.

Conclusions

In total 19% in an in-pharmacy screening were unaware of their elevated TC of ≥6.2 mmol/L. We also identified characteristics that could be used reach those who are less likely to have measured TC and BG.

Association of predicted 10 years cardiovascular mortality risk with duration of HIV infection and antiretroviral therapy among HIV-infected individuals in Durban, South Africa

BACKGROUND

South Africa has the largest population of human immunodeficiency virus (HIV) infected patients on antiretroviral therapy (ART) realising the benefits of increased life expectancy. However, this population may be susceptible to cardiovascular disease (CVD) development, due to the chronic consequences of a lifestyle-related combination of risk factors, HIV infection and ART. We predicted a 10-year cardiovascular mortality risk in an HIV-infected population on long-term ART, based on their observed metabolic risk factor profile.

METHODS

We extracted data from hospital medical charts for 384 randomly selected HIV-infected patients aged ≥ 30 years. We defined metabolic syndrome (MetS) subcomponents using the International Diabetes Federation definition. A validated non-laboratory-based model for predicting a 10-year CVD mortality risk was applied and categorised into five levels, with the thresholds ranging from very low-risk (< 5%) to very high-risk scores (> 30%).

RESULTS

Among the 384 patients, with a mean (± standard deviation) age of 42.90 ± 8.20 years, the proportion of patients that were overweight/obese was 53.3%, where 50.9% had low high-density lipoprotein (HDL) cholesterol and 21 (17.5%) had metabolic syndrome. A total of 144 patients with complete data allowed a definitive prediction of a 10-year CVD mortality risk. 52% (95% CI 44-60) of the patients were stratified to very low risk (< 5%) compared to 8% (95% CI 4-13) that were at a very high risk (> 30%) of 10-year CVD mortality. The CVD risk grows with increasing age (years), 57.82 ± 6.27 among very high risk and 37.52 ± 4.50; p < 0.001 in very low risk patients. Adjusting for age and analysing CVD risk mortality as a continuous risk score, increasing duration of HIV infection (p = 0.002) and ART (p = 0.007) were significantly associated with increased predicted 10 year CVD mortality risk. However, there was no association between these factors and categorised CVD mortality risk as per recommended scoring thresholds.

CONCLUSIONS

Approximately 1 in 10 HIV-infected patients is at very high risk of predicted 10-year CVD mortality in our study population. Like uninfected individuals, our study found increased age as a major predictor of 10-year mortality risk and high prevalence of metabolic syndrome. Additional CVD mortality risk due to the duration of HIV infection and ART was seen in our population, further studies in larger and more representative study samples are encouraged. It recommends an urgent need for early planning, prevention and management of metabolic risk factors in HIV populations, at the point of ART initiation.