Imaging-based body fat depots and new-onset atrial fibrillation in general population

Background

Obesity is a well-established risk factor for incident atrial fibrillation (AF). Whether different body fat depots differentially associate with AF development remains largely unknown.

Purpose

We aimed to investigate the associations between various body fat depots and the risk of new-onset AF among middle-aged and elderly individuals from general population.

Methods

In the prospective population-based cohort study, body composition was assessed using dual-energy X-ray absorptiometry (DXA) and total body mass, lean mass, fat mass, android and gynoid fat were analyzed (N=3468). Liver fat and epicardial fat were assessed using computed tomography (CT) (N=2145). A body fat score was defined by adding tertiles of each fat depot. All participants were followed for the occurrence of AF until 1st Jan. 2014. Principle component analysis was conducted to identify body fat distribution patterns. Time-to-event analyses were performed using Cox proportional hazards regression analysis. Hazard ratios (HR) and 95% confidence-intervals (95% CI), adjusted for cardiovascular risk factors, were calculated.

Results

Mean (standard deviation) of age for participants in DXA study and CT study was 74.42 (6.85) and 68.66 (6.41) years, respectively. AF incidence rate was 13.1 per 1000 person-years during a median follow-up time of 9.62 years. In the adjusted model, fat mass (HR; 95% CI: 1.33; 1.05–1.68), lean mass (1.40; 1.15–1.72), gynoid fat mass (1.36; 1.12–1.65), and total body mass (1.51; 1.21–1.89) were significantly associated with new-onset AF. Of note, android-to-gynoid fat ratio was inversely associated with incident AF (HR; 95% CI: 0.81; 0.70–0.94). Larger body fat score was associated with increased risk of incident AF (P for trend <0.01). Two fat distribution patterns were identified. Adherence to the fat- and gynoid fat- pattern (P for trend = 0.035), but not muscle- and visceral fat- pattern (P for trend = 0.35), was significantly associated with larger risk of new-onset AF.

Conclusions

Various body fat depots were associated with new-onset AF. Larger values of total body mass carried the highest risk for incident AF. The inverse association between android to gynoid fat ratio with AF presents a novel finding. A significant dose-response relationship between body fat accumulation and risk of new-onset AF was observed, implying a collective impact of fat depots on AF development. Findings also suggest that various fat depots, characterized by different fat distribution patterns, may exert differential combined effect on the risk of incident AF.

Funding Acknowledgement

Type of funding sources: None. Fat depots and atrial fibrillation

Sex-specific reference values and determinants of infra-renal abdominal aortic diameter among women and men from general population

Introduction

Abdominal aortic diameter has shown to be a marker of adverse cardiovascular outcomes. Among the non-aneurysmal populations, studies regarding abdominal aortic diameter normal reference values are sparse. Moreover, data regarding the associations between cardiovascular risk factors and aortic diameter among men and women are limited.

Purpose

To establish age- and sex-specific distribution of the infra-renal abdominal aortic diameters among non-aneurysmal older adults from the general population and to investigate the associations between cardiovascular risk factors and aortic diameters in men and women.

Methods

From a population-based cohort, 4032 participants (mean age, 67.2 years; 60.4% women) with infra-renal diameter assessment and without history of cardiovascular disease were included. Mean and quantile values of diameters were calculated in different age groups. Multiple linear regression analysis was used to detect the association of cardiovascular risk factors with diameters in men and women.

Results

The mean crude diameter was larger in men [mean (SD): 19.5 (2.6) mm] compared to women [17.0 (2.4)mm] but after adjustment for body surface area (BSA), the differences were small. There was a non-linear relationship between age and diameter (p<0.001). After 66 years of age, the increase in diameter with increasing age was attenuated. After age 74 years in women and 71 years in men, the relationship between age and infra-renal aortic diameter was no longer statistically significant (Figure). Waist [standardized β (95% CI): 0.02 (0.0–0.04) in women and 0.03 (0.01–0.06) in men] and diastolic blood pressure [0.04 (0.02–0.05) in women and 0.02 (0.0–0.04) in men] were the risk factors for diameters in both sexes. Body mass index [0.02 (0.01–0.09)], systolic blood pressure [−0.01 (−0.02 to −0.01)], smoking status [0.21 (0.02–0.39)], cholesterol [−0.19 (−0.29 to −0.09)], and lipid-lowering medication [−0.47 (−0.71 to −0.23)] were significantly associated with aortic diameter only in women.

Conclusion

The differences in the crude abdominal aortic diameter between women and men diminished after taking into account the BSA. The abdominal aortic diameter increased steeply with advancing age and up to 66 years of age. However, after 74 years in women and 71 years in men, the diameter values reached a plateau. We also observed sex differences in the associations of cardiovascular risk factors with abdominal aortic diameter.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Netherlands Organization for the Health Research and Development (ZonMw); the Research Institute for Diseases in the Elderly (RIDE)