In Reply We recently reported that high body mass index (BMI) and low aerobic fitness in a large cohort of 18-year-old Swedish men were associated with increased risk of hypertension in adulthood. Hypertension was ascertained using all inpatient diagnoses nationwide throughout the study period (1969-2012) and outpatient diagnoses from all specialty clinics between 2001 and 2012. We indicated that hypertension was therefore underreported because we lacked outpatient data before 2001 or from primary care clinics. Dr Brunström raises the question of whether our findings may be attributable to the known associations between high BMI or low aerobic fitness and coronary heart disease or stroke that are likely to receive inpatient or specialty clinic treatment and are also associated with hypertension.
Crump C, Sundquist J, Sundquist K. Hypertension, the Swedish Patient Register, and Selection Bias—Reply. JAMA Intern Med. 2016;176(6):863. doi:10.1001/jamainternmed.2016.1562