Objective  To examine the interactive effect of family hypertension history and overweight/obesity on hypertension and to provide references for hypertension prevention and treatment.

  Methods  We conducted a questionnaire interview and physical examination among all employees (n = 1 250) in a science research institute in Beijing city from September to December 2017. Logistic regression model was adopted to analyze the correlation between family history of hypertension and overweight/obesity and additive model was used to analyze the interaction between the two variables.

  Results  Among all the employees, 273 hypertensives were identified and the hypertension prevalence rate was 21.84%. Of the employees, 60.80% (760) reported a family history of hypertension and 48.72% (609) were assessed with overweight/obesity (with the body mass indexes of ≥ 24.0 kg/m²). After adjusting for potential confounding factors such as age, sex, monthly income, education, smoking alcohol, drinking, and sleeping time, multivariate logistic regression analyses revealed that the participants with family history of hypertension had a 2.59 times higher risk of hypertension (odds ratio OR = 2.59, 95% confidence interval 95% CI: 1.38 – 4.84) than those without the history; the participants with overweight/obesity had a 3.21 times higher risk of hypertension compared to those with normal body weight (OR = 3.21, 95% CI: 1.66 – 6.21); and the participants with both family history of hypertension and overweight/obesity had a 7.64 times higher risk of hypertension in comparison with those with neither the history nor overweight/obesity (OR = 7.64, 95% CI: 4.21 – 13.89). Further interaction analysis resulted in following indices for the interactive effect of family history of hypertension and overweight/obesity on hypertension: relative excess risk due to interaction (RERI) of 2.85 (95% CI: 0.35 – 5.35), attributable proportion (AP) of 0.37 (95% CI: 0.13 – 0.62), interaction index of 1.75, (95% CI: 1.06 – 2.89), and pure interaction attributable proportion (AP*) of 42.8%, respectively, indicating an additive interactive effect of the two variables on hypertension.

  Conclusion  Both family history of hypertension and being overweight/obese can increase the risk of hypertension and the interaction between the two variables increases the risk of hypertension.