Search

Background Isotemporal substitution examines the effect on health outcomes of replacing sedentary time with light‐intensity physical activity or moderate‐to‐vigorous intensity physical activity; however, existing studies are limited by cross‐sectional study designs. Methods and Results Participants were 1922 adults from the CARDIA (Coronary Artery Risk Development in Young Adults) study. Linear regression examined the associations of sedentary, light‐intensity physical activity, and moderate‐to‐vigorous intensity physical activity at year 20 (2005–2006) with waist circumference, blood pressure, glucose, insulin, triglycerides, high‐density lipoprotein cholesterol, and a composite risk score at year 30 (2015–2016). Models then examined change in activity with change in cardiometabolic risk over the same 10‐year period. Replacing 30 min/day of sedentary time with 30 min/day of light‐intensity physical activity at year 20 was associated with a lower composite risk score (−0.01 SD [95% CI, −0.02, −0.00]) at year 30, characterized by lower waist circumference (0.15 cm [95% CI, −0.27, 0.02]), insulin (0.20 μU/mL [95% CI, −0.35, −0.04]), and higher high‐density lipoprotein cholesterol (0.20 mg/dL [95% CI, 0.00, 0.40]; all P

BackgroundThe concept of ideal cardiovascular health (CVH), defined by the American Heart Association primarily for coronary heart disease and stroke prevention, may apply to diabetes mellitus prevention among blacks. Methods and ResultsOur sample included 2668 adults in the Jackson Heart Study with complete baseline data on 6 of 7 American Heart Association CVH metrics (body mass index, healthy diet, smoking, total cholesterol, blood pressure, and physical activity). Incident diabetes mellitus was defined as fasting glucose ≥126 mg/dL, physician diagnosis, use of diabetes mellitus drugs, or glycosylated hemoglobin ≥6.5%. A summary CVH score from 0 to 6, based on presence/absence of ideal CVH metrics, was derived for each participant. Cox regression was used to estimate adjusted hazard ratios. Mean age was 55 years (65% women) with 492 incident diabetes mellitus events over 7.6 years (24.6 cases/1000 person‐years). Three quarters of participants had only 1 or 2 ideal CVH metrics; no participant had all 6. After adjustment for demographic factors (age, sex, education, and income) and high‐sensitivity C‐reactive protein, each additional ideal CVH metric was associated with a 17% diabetes mellitus risk reduction (hazard ratio, 0.83; 95% CI, 0.74–0.93). The association was attenuated with further adjustment for homeostasis model assessment for insulin resistance (hazard ratio, 0.89; 95% CI, 0.79–1.00). Compared with participants with 1 or no ideal CVH metric, diabetes mellitus risk was 15% and 37% lower in those with 2 and ≥3 ideal CVH metrics, respectively. ConclusionsThe AHA concept of ideal CVH is applicable to diabetes mellitus prevention among blacks. These associations were largely explained by insulin resistance.

BackgroundDespite evidence suggesting that early metabolic dysfunction impacts cardiovascular disease risk, current guidelines focus on risk assessments later in life, missing early transitions in metabolic risk that may represent opportunities for averting the development of cardiovascular disease. Methods and ResultsIn 4420 young adults in the Coronary Artery Risk Development in Young Adults (CARDIA) study, we defined a “metabolic” risk score based on components of the Third Report of the Adult Treatment Panel's definition of metabolic syndrome. Using latent class trajectory analysis adjusted for sex, race, and time‐dependent body mass index, we identified 6 distinct metabolic trajectories over time, specified by initial and final risk: low‐stable, low‐worsening, high‐stable, intermediate‐worsening, intermediate‐stable, and high‐worsening. Overall, individuals gained weight over time in CARDIA with statistically but not clinically different body mass index trend over time. Dysglycemia and dyslipidemia over time were highest in initially high or worsening trajectory groups. Divergence in metabolic trajectories occurred in early adulthood (before age 40), with 2 of 3 individuals experiencing an increase in metabolic risk over time. Membership in a higher‐risk trajectory (defined as initially high or worsening over time) was associated with greater prevalence and extent of coronary artery calcification, left ventricular mass, and decreased left ventricular strain at year 25. Importantly, despite similar rise in body mass index across trajectories over 25 years, coronary artery calcification and left ventricular structure and function more closely tracked risk factor trajectories. ConclusionsTransitions in metabolic risk occur early in life. Obesity‐related metabolic dysfunction is related to subclinical cardiovascular phenotypes independent of evolution in body mass index, including coronary artery calcification and myocardial hypertrophy and dysfunction.