The American Heart Association (AHA) recommends that Americans adhere to the construct of ideal cardiovascular health (CVH) for primary prevention of atherosclerotic cardiovascular disease (ASCVD). The life's Simple 7 (LS7) metrics describe ideal, intermediate, and poor levels of cardiovascular disease risk factors or behaviors, including smoking, body mass index (BMI), physical activity, diet, total cholesterol, blood pressure, and fasting glucose [1]. More recently the AHA has updated their CVH construct to the Life's Essential 8 (LE8) which adds sleep to the other 7 metrics [2]. Large epidemiological studies have shown that the number of LS7 factors at ideal levels is strongly and inversely associated with incidence of ASCVD [3,4]. Much of these data were derived from non-South Asian (SA) populations, and it remains unclear whether cultivating healthy lifestyle habits may mitigate ASCVD risk in SA to the same degree as in other race/ethnic groups.

SA individuals suffer higher rates of coronary artery disease at younger ages compared with other ethnic groups [[5], [6], [7]], carrying a risk almost double that of European adults [8]. Data from registries, such as the INTERHEART study, have shown that the heightened risk of premature ASCVD in SA may be linked to a clustering of traditional risk factors, specifically, hypertension, diabetes, obesity/overweight status, and lower levels of protective factors such as regular physical activity and diets high in fruits and vegetables [6] Genetic predisposition (including higher levels of lipoprotein (a), higher levels of triglycerides, lower levels of high density lipoprotein cholesterol (HDL-C), and differences in body fat distribution) may also exert some influence [9]. Recent evidence from the UK Biobank and the National Health Interview Survey support these findings [8,10].

Prospective, observational cohort data with ASCVD events in American SA are lacking, though are expected as the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study matures [11]. The presence of coronary artery calcium (CAC), a marker of subclinical coronary atherosclerosis, is associated with an increased risk of future ASCVD events and is a useful upstream prognostic marker to guide shared decision making about preventive strategies [12,13]. Describing the risk of developing CAC over time across LS7 strata may further help identify higher risk groups who may benefit from CAC testing to help facilitate optimal treatment with intensive risk factor modification. Alternatively, low risk groups, such as those with favorable LS7 and a CAC score of 0 could then be encouraged to continue healthy lifestyle habits and update cardiovascular risk factor screening as a passage to healthy aging.

Achieving a higher number of LS7 metrics is inversely associated with CAC incidence, however, limited data are available describing the relationship between attainment of ideal CVH metrics and CAC incidence and progression, particularly among SA compared with other ethnicities [14]. These data can inform prevention recommendations for SA populations. The primary objective of this analysis is to determine if LS7 metrics predict the incidence and progression of CAC in the SA population. Key secondary analyses are to evaluate the distribution of LS7 metrics and CAC incidence in adults from the MASALA population and to determine if the LS7 metrics more strongly predict incidence and progression of CAC in South Asians, compared to other race/ethnic groups in the Multi-Ethnic Study of Atherosclerosis (MESA).