Additive interaction of family medical history of cardiovascular diseases with hypertension and diabetes on the diagnosis of cardiovascular diseases among older adults in India

Abstract

Introduction: The present study aimed to examine the additive interaction of family medical history of cardiovascular disease (CVD) and self-reported hypertension and diabetes on the diagnosis of CVD among older adults aged 45 years and above in India. A family medical history of CVD in individuals with hypertension and diabetes could identify a subpopulation with a higher risk of CVD.

Methods: The study used the data from the Longitudinal Ageing Study in India (LASI) Wave 1 (2017-2018). The total sample size for the study was 58,734 older adults aged 45 years and above. An additive model was applied to determine the additive interaction effect of the family medical history of CVD with hypertension and diabetes on the diagnosis of CVD by calculating three different measures of additive interaction: the relative excess risk due to interaction (RERI), attribution proportion due to interaction (AP), and synergy index (S).

Results: The prevalence of CVD was higher among hypertensive individuals with a family medical history of CVD (18.6%) than individuals without the coexistence of family medical history of CVD and hypertension (4.7%), and hypertensive individuals without family medical history of CVD (11.3%). On the other hand, the prevalence of CVD was higher among individuals with diabetes and family history of CVD (20.5%) than individuals without the coexistence of family history of CVD and diabetes (5.0%). Individuals with parental and sibling medical history had two times higher odds of having chronic heart diseases and strokes, respectively than those without parental and sibling history. In the adjusted model, RERI, AP, and S for CVD were 2.30 (95% CI: 0.87-3.74), 35% (0.35; 95% CI: 0.20-0.51), and 1.71 (95% CI: 1.27-2.28) respectively, demonstrating significant positive interaction between family medical history and hypertension on the diagnosis of cardiovascular diseases.

Conclusions: The present study revealed that in the additive model, the interaction effects of family medical history and hypertension were significantly positive on cardiovascular diseases even after adjustment with potential confounding factors. Therefore, it is crucial to consider the presence of family medical history of CVD among individuals with hypertension and diabetes measured in research and clinical practice.

Keywords: India; additive interaction; cardiovascular diseases; diabetes; family medical history; hypertension; older adults; synergistic effect.

Figure 1

Study sample flowchart.

Figure 2

Multivariable logistic estimates for cardiovascular diseases according to key predictor variables among individuals aged 45 and above. Odds ratio, adjusted for age, sex, education, working, marital status, residence, MPCE, religion, caste, region, physical inactivity, smoking, chewing tobacco, alcohol consumption, body mass index, ADL and IADL. FH, family medical history (family history of chronic heart diseases, stroke, and cardiovascular diseases).

Figure 3

Additive interaction of family medical history of CVD with hypertension on cardiovascular diseases among individuals aged 45 and above in India. FH, family medical history (family history of chronic heart diseases, stroke, and cardiovascular diseases); HT, hypertension. Interaction exists if RERI ! = 0 or AP ! = 0 or S ! = 1. Estimates for Additive Interaction, adjusted for age, sex, education, working, marital status, residence, MPCE, religion, caste, region, physical inactivity, smoking, chewing tobacco, alcohol consumption, body mass index (BMI), ADL and IADL. RERI, Relative excess risk due to interaction; AP, Attributable proportion, AP, the attributable proportion, has been presented in the result as a percentage after multiplied by 100. S, Synergy index.

Figure 4

Additive interaction of family medical history of CVD with diabetes on cardiovascular diseases among individuals aged 45 and above in India. FH, family medical history (family history of chronic heart diseases, stroke, and cardiovascular diseases); Db, diabetes. Interaction exists if RERI ! = 0 or AP ! = 0 or S ! = 1. Estimates for Additive Interaction, adjusted for age, sex, education, working, marital status, residence, MPCE, religion, caste, region, physical inactivity, smoking, chewing tobacco, alcohol consumption, body mass index (BMI), ADL and IADL. RERI, Relative excess risk due to interaction. AP, Attributable proportion, AP, the attributable proportion, has been presented in the result as a percentage after multiplied by 100. S, Synergy index.