Abstract P301: Age Differences in the Association between Waist-to-height Ratio and Risk of Cardiovascular Disease: The Suita Study

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Introduction: Waist-to-heightratio (WHtR) has been shown to be useful global screening tool forcardiovascular disease (CVD) in the recent meta-analysis. The impact of WHtR on the risks of CVD by age is not well known. Hypothesis: We assessed whether the association between WHtR and the risks of CVD was different by age categories. Methods: This study is a population-based cohort study in an urban area of Japan. Study participants comprised 5,488 Japanese urban residents (2,600 men and 2,888 women) aged 30-83 years with no history of CVD. At baseline (1989–1994), waist circumference was measured at the umbilical level and height with bare feet was measured. WHtR was calculated as waist circumference (cm) divided by height (cm). The criteria of myocardial infarction were based on the WHO Monitoring of Trends and Determinants in Cardiovascular Disease Projects. In addition to myocardial infarction, we also evaluated coronary angioplasty, coronary artery bypass grafting and sudden cardiac death, all of which were defined as coronary heart disease (CHD). A stroke was defined according to criteria from the US National Survey of Stroke and confirmed by computed tomography. We stratified participants by sex and age groups (30–49, 50–69 and 70–83 years). The Cox proportional hazard ratios (HRs) and 95% confidence intervals (95% CIs) for CVD according to the quartiles of WHtR were calculated after adjustment for age, smoking and drinking status. Results: During the follow-up period (13.0 years in average), 428 CVD events (184 CHD and 244 strokes) were observed. Men with the highest quartile of WHtR aged 50–69 years had significantly increased the risks of CVD and CHD, compared with the lowest quartile; the HRs (95% CIs) were 1.81 (1.13–2.90) and 2.47 (1.17–5.20), respectively. There were statistically significant linear increases in the HRs of CVD ( p for trend =0.01), CHD ( p for trend =0.02) and cerebral infarction ( p for trend =0.03) in this group. Women with the highest quartile of WHtR aged 50–69 years had significantly increased the risks of stroke; the HRs (95% CIs) was 2.43 (1.01–5.84). There were statistically significant linear increases in the HRs of CVD ( p for trend =0.04) and stroke ( p for trend =0.04) in this group. However, the similar results were not observed in the other age groups in both sexes. We observed a significant interaction between age groups and WHtR categories for the risks of CVD in men ( p for interaction=0.02). Conclusions: The association between WHtR and CVD was different among age groups. WHtR could be useful to predict the risks of CVD in middle aged men and women.