Anthropometric Indices As Predictors of Coronary Heart Disease Risk: Joint Modeling of Longitudinal Measurements and Time To Event

Background: the prevalence of overweight and obesity have increased dramatically worldwide and together they constitute a major risk factor for coronary heart disease (chd). the aim of this study was to assess the repeated mea-surements of body mass index (bmi), waist circumference (wc), waist to hip ratio (whr) and waist to height ratio (whtr) in predicting chd incidence. methods: this longitudinal study was conducted within the framework of the tehran lipid and glucose study between 1999–2011, on 1959 women and 1371 men participants’ ages ≥30 yr, without a history of cvd. a joint modeling approach was utilized for data analysis using r software. the resulting joint model allowed measuring α (quantifies the association between anthropometric indices up to time t and the hazard for chd event at the same time point). results: about 9% of the participants (7.1% of the women and 11.7% of the men) experienced chd event during follow-up. the results indicated a significant linear increasing trend in bmi, wc, whr, and whtr over time (p<0.001). the increased risk of chd event in females increases with the values of bmi (α= 0.004, p=0.023), wc (α= 0.018, p=0.009), whr (α= 0.067, p=0.014) and whtr (α= 0.106, p=0.002). furthermore, in males the risk of chd risk increases by the values of bmi (α= 0.005, p=0.032), wc (α= 0.019, p=0.008), whr (α= 0.043, p=0.015) and whtr (α= 0.096, p=0.002). conclusion: by jointly modeling longitudinal data with time-to-event outcomes, our study revealed that whtr is su-perior to other indices in predicting chd incidence.