Cardiovascular Journal of Africa: Vol 32 No 5 (SEPTEMBER/OCTOBER 2021)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 5, September/October 2021 AFRICA 283 Striking association of cardiovascular risk factors with late-life cognitive decline An increase in risk factors for cardiovascular disease (CVD) during young adulthood is associated with cognitive decline in late life, a US data analysis shows. Investigators found a ‘novel, striking’ association between high body mass index (BMI), elevated systolic blood pressure, and high glucose levels among adults in their 20s and 30s and a doubling of the average rate of cognitive decline over a 10-year period in late life. ‘These results are striking and suggest that early adulthood may be a critical time for the relationship between these health issues and late-life cognitive skills,’ study investigator Dr Kristine Yaffe, professor of psychiatry, neurology, and epidemiology, University of California-San Francisco, said. ‘It’s possible that treating or modifying these health issues in early adulthood could prevent or reduce problems with thinking skills in later life,’ she added. The investigators noted that CVD risk factors are associated with an increased risk for cognitive decline, but little is known as to how early CVD risk factors influence late-life cognition. To examine the impact of these risk factors on cognition, the researchers pooled data from four prospective studies: the Coronary Artery Risk Development in Young Adults (CARDIA) study, the Multi Ethnic Study of Atherosclerosis (MESA), the Cardiovascular Health Study (CHS), and the Health, Aging and Body Composition (Health ABC) study ( n = 15 001 participants aged 18–95 years). On the basis of previous epidemiologic research of CVD risk factors associated with cognitive decline, the investigators focused on BMI, fasting glucose level, systolic blood pressure and total cholesterol level. They used data from the four studies to examine early adult and mid-life trajectories of these risk factors for each participant in the two older cohorts, those of the Health ABC and CHS studies. To assess cognitive outcomes, the investigators examined participants’ scores on the Digit Symbol Substitution Test (DSST) and the Modified Mini-Mental State Exam. The former test measures processing speed and executive function; the latter evaluates global cognition. These tests were administered every one to two years. Levels of CVD risk factors were higher among older participants than among their younger counterparts, but smoking was more prevalent among younger participants. The mean age of the two pooled older cohorts was 72 years. BMI, fasting glucose level and systolic blood pressure were elevated in fewer than 5% of these participants during early adulthood. Among approximately 40% of older participants, cholesterol levels were elevated at that time. Among approximately 20% of older participants, BMI and systolic blood pressure were elevated at mid-life. At mid-life, fasting glucose levels were elevated for 10% of participants, and cholesterol levels were elevated for 68%. In late life, BMI was elevated for 15% of participants, fasting glucose levels were elevated for 9%, systolic blood pressure was elevated for 24%, and cholesterol levels were elevated for 43%. Elevated BMI during early adulthood was associated with an increase in cognitive decline of three to four points over 10 years in late life. High systolic blood pressure was associated with a four-point increase in decline on DSST in late life. Although fasting glucose levels were elevated in few participants during early adulthood, the data suggest such elevations are associated with increased late-life cognitive decline. However, high cholesterol levels in early adulthood were not a significant risk factor for cognitive decline. ‘The evidence for cholesterol and late-life cognitive decline is mixed, but our findings may suggest that other cardiovascular risk factors, such as blood pressure, BMI and fasting glucose level in early adulthood, are more critical than cholesterol,’ said Yaffe. The associations between elevated cardiovascular risk factors at mid-life and cognition in late life were less consistent. Elevated BMI, systolic blood pressure and fasting glucose levels in late life were associated with cognitive gains in very late life. ‘Clinicians could be more aware that cardiovascular health is important for brain health, even if you’re not an older adult, and also share this information with their patients,’ said Yaffe. Yaffe added that her team plans to investigate associations between CVD risk factors and cognition throughout life. In particular, they want to examine the transition of cognitive continued on page 286 … 24. Navinan MR, Yudhishdran J, Herath S, et al. Complete heart block in dengue complicating management of shock due to both bleeding and leakage: a case report. BMC Res Notes 2015; 8 : 68. 25. Sharda M, Gupt A, Nagar D, et al. Dengue fever: an additional cause for bradycardia. J Assoc Physicians India . 2014; 62 (4): 362–363. 26. 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