Abstract 1037: Parental Occurrence of Intermittent Claudication is an Independent Risk Factor for Intermittent Claudication in Adult Offspring: The Framingham Heart Study
Introduction: Peripheral arterial disease (PAD) affects approximately 8 million people in the United States. Studies suggest that there is an inherited component of PAD; however, no study has quantified the extent to which these influences are independent of risk factors. Our objective was to prospectively examine whether intermittent claudication (IC) in parents increased risk for IC in adult offspring independent of established cardiovascular risk factors.
Methods: The study sample consisted of offspring participants aged greater than or equal to 30 years with both parents enrolled in the original cohort of the Framingham Heart Study and free of cardiovascular disease (CVD) at three baseline examinations (n= 2970 unique participants, 53% women). In both parents and offspring, IC was adjudicated by a panel of three investigators and defined as exertional cramping discomfort in the calf appearing sooner with rapid or uphill walking and relieved with rest. Data from the three exams, each with 12 years of follow-up were pooled. Cox proportional hazards regression was used to examine the 12 year risk for incident IC in offspring associated with parental IC adjusting for age, sex, diabetes, smoking, systolic blood pressure, anti-hypertensive treatment, total cholesterol, and HDL cholesterol. In secondary analysis we additionally adjusted for interim CVD.
Results: Among 909 person-exams in the parental IC history group (mean age 49.9 years) and 5397 person-exams in the no parental IC history group (mean age 47.6 years) there were 101 incident IC events during follow-up. Baseline risk factors were more prevalent in the parental IC group compared with the no parental IC group. Parental history of IC significantly increased the risk of incident IC in offspring (multivariable adjusted hazard ratio of 1.81, 95% CI 1.14, 2.88). There was no change with adjustment for interim development of CVD (multivariable adjusted hazard ratio 1.81, 95% CI 1.14, 2.86).
Conclusion: IC in parents increases risk for IC in adult offspring independent of established risk factors. These data suggest that there is a genetic component of PAD and support future research into genetic causes.