Background: Adipose tissue distribution (adiposity phenotype) differs across sex and ethnic groups, and these variations may contribute to differences in cardiovascular (CV) disease risk and prevalence. In non-Indigenous populations, higher levels of abdominal visceral fat and epicardial fat have been associated with increased CV risk independent of overall adiposity. To date, very few studies have explored how different adiposity phenotypes relate to CV risk in First Nations adults, particularly from a sex-specific perspective. The aim of this analysis was to compare sex-specific adiposity phenotypes in First Nations adults and examine their relationship with CV risk as measured by the INTERHEART score.
METHODS AND RESULTS: 1302 adults from 8 First Nations communities across Canada were recruited to participate in The Canadian Alliance for Healthy Hearts and Minds-First Nations pan-Canadian study. Abdominal visceral fat and cardiac (epicardial) fat volumes were measured by magnetic resonance imaging. Demographic and anthropometric data were collected. CV risk was estimated according to the INTERHEART score (low ≤ 9, moderate 10-15, high ≥ 16). This analysis focuses on participants from the Wendat Nation. Participants (n=173), whose mean age was 49±12y, had a body mass index of 29.3±5.4kg/m² and waist circumference of 103.1±15.8cm (men) and 90.2±16.0cm (women). Men had higher visceral (96.4±47.6ml vs. 70.2±35.2ml) and epicardial (11.4±3.9ml vs. 9.4±3.0ml) fat volumes compared with women (all p< 0.001). Visceral fat was associated with epicardial fat in both sexes (men: r=0.28; p=0.03 and women: r=0.62; p< 0.001). Among men and women, visceral fat was significantly higher in the high CV risk group compared to the low (p < 0.05) and moderate (p < 0.01) risk groups, after adjusting for age. After adjusting for age, higher epicardial fat volume was observed in women the high CV risk group compared to those in the low-risk group (p=0.007).
Conclusion: In the Wendat First Nations population, visceral adiposity is associated with elevated CV risk in both sexes. In women, epicardial fat accumulation is associated with higher CV risk. These results suggest that sex-specific variations exist in the associations between fat deposition and CV risk in the Wendat population. Targeted interventions aimed at reducing abdominal adiposity could be effective in lowering CV risk.
