Sex Differences in the Association Between Measures of General and Central Adiposity and the Risk of Myocardial Infarction: Results From the UK Biobank

Abstract

Background: There are substantial differences in the distribution of adipose tissue between women and men. We assessed the sex-specific relationships and their differences between measures of general and central adiposity and the risk of incident myocardial infarction (MI).

Methods and results: Between 2006 and 2010, the UK Biobank recruited over 500 000 participants aged 40 to 69 years across the United Kingdom. During 7 years of follow-up, 5710 cases of MI (28% women) were recorded among 265 988 women and 213 622 men without a history of cardiovascular disease at baseline. Cox regression models yielded adjusted hazard ratios for MI associated with body mass index, waist circumference, waist-to-hip ratio, and waist-to-height ratio. There was an approximate log-linear relationship between measures of general and central adiposity and the risk of MI in both sexes. A 1-SD higher in body mass index, waist circumference, waist-to-hip ratio, and waist-to-height ratio, respectively, were associated with hazard ratios (confidence intervals) for MI of 1.22 (1.17; 1.28), 1.35 (1.28; 1.42), 1.49 (1.39; 1.59), and 1.34 (1.27; 1.40) in women and of 1.28 (1.23; 1.32), 1.28 (1.23; 1.33), 1.36 (1.30; 1.43), and 1.33 (1.28; 1.38) in men. The corresponding women-to-men ratios of hazard ratios were 0.96 (0.91; 1.02), 1.07 (1.00; 1.14), 1.15 (1.06; 1.24), and 1.03 (0.97; 1.09).

Conclusions: Although general and central adiposity measures each have profound deleterious effects on the risk of MI in both sexes, a higher waist circumference and waist-to-hip ratio conferred a greater excess risk of MI in women than in men. Waist-to-hip ratio was more strongly associated with the risk of MI than body mass index in both sexes, especially in women.

Keywords: adipose tissue; men; myocardial infarction; women.

Figure 1

Adjusted hazard ratios (HRs) for incident myocardial infarction associated with body mass index, waist circumference, waist‐to‐hip ratio, and waist‐to‐height ratio. Analyses are adjusted for age, Townsend deprivation index, and smoking status. The first 2 years of follow‐up were excluded. HRs per fifth are plotted on a floating absolute scale, with the second fifth as the reference group. Vertical lines indicate the corresponding 95% confidence intervals. HRs for a 1‐SD higher value are shown for each sex, taking the standard deviation from the sex‐combined baseline data. *P‐value for interaction by sex for the continuous analysis.

Figure 2

Ratio of women‐to‐men hazard ratios for incident MI associated with anthropometric measures, by age, socioeconomic status, and body mass index (where applicable). Analyses are adjusted for age, Townsend deprivation index, and smoking status, where appropriate. The first 2 years of follow‐up were excluded. CI indicates confidence interval; HR, hazard ratio; MI, myocardial infarction; RHR, ratio of hazard ratios; SES, socioeconomic status.

Figure 3

Ratio of women‐to‐men hazard ratios for incident MI per 1–standard deviation higher value for each comparison of anthropometric measures, by sex. Analyses are adjusted for age, Townsend deprivation index, and smoking status. The first 2 years of follow‐up were excluded. The standard deviation is taken from the sex‐combined baseline data. BMI indicates body mass index; CI, confidence interval; HR, hazard ratio; MI, myocardial infarction; RHR, ratio of hazard ratios; WC, waist circumference; WHR, waist‐to‐hip ratio; WHtR, waist‐to‐height ratio.