Neuropsychological test performance, cognitive functioning, blood pressure, and age: the Framingham Heart Study

Interactions of three indices of blood pressure (systolic blood pressure, diastolic blood pressure, and chronicity of hypertension) and age-cohort membership were examined for a sample of 1,695 stroke-free participants of the Framingham Heart Study, ages 55-88 years. Blood pressure level and chronicity of hypertension were assessed over five biennial examinations performed between 1956 and 1964, a time when few hypertensives were being treated, and were related to neuropsychological tests administered between 1976 and 1978. Multiple linear regression methods were used to examine Age x Blood Pressure (or Chronicity of Hypertension) interactions in alternative analyses involving three age groups (55-64 years, 65-74 years, and 75-88 years) and age as a continuously distributed variable (age in years). Interactions were either statistically nonsignificant or trivial with respect to magnitude of effect. This was true when interaction terms (Age x Blood Pressure Level or Age x Chronicity of Hypertension) were controlled for blood pressure, age, education, occupation, cigarette smoking, alcohol consumption, gender, and antihypertensive treatment. The Age x Blood Pressure model as it pertains to older adults was not supported, but independent associations (with all covariables controlled) between the indices of blood pressure and cognitive functioning were statistically significant.