Pekka Jousilahti

The aim of this study was to test the agreement between nighttime home and nighttime ambulatory blood pressure (BP) and to compare their associations with hypertensive end-organ damage for the first time in the general population. A population sample of 248 participants underwent measurements for nighttime home BP (3 measurements on 2 nights with a timer-equipped home device), nighttime ambulatory BP, pulse wave velocity (PWV), carotid intima-media thickness (IMT) and echocardiographic left ventricular mass index (LVMI). No significant differences were observed between mean nighttime home and ambulatory BPs (systolic/diastolic difference: 0.7 ± 7.6/0.2 ± 6.0 mmHg, p = 0.16/0.64). Furthermore, no systematic differences in systolic or diastolic nighttime BPs were identified between the two methods in Bland-Altman plots (Figure). All nighttime home and ambulatory BPs were positively correlated with PWV, IMT and LVMI (p < 0.01 for all). Correlation coefficients for BP indices and end-organ damage and their comparisons are shown in the Table. No significant differences in Pearson's correlation coefficients between end-organ damage and nighttime home or ambulatory BP were observed (p ≥ 0.11 for all comparisons using Dunn and Clark's Z), except for a slightly stronger correlation between PWV and ambulatory systolic BP than for home systolic BP (r = 0.57 vs. 0.50, p = 0.03). The adjusted R2 of all multivariable-adjusted models for PWV, IMT or LVMI that included nighttime home or ambulatory systolic/diastolic BP were within 2/1%. Our study demonstrates that nighttime home and ambulatory measurements produce similar BP values that have comparable associations with end-organ damage in the general population even when a clinically feasible measurement protocol is used for measuring nighttime home BP. In the future, nighttime home BP measurement may offer a feasible and easily accessible alternative to ambulatory monitoring for the measurement of nighttime BP.

We evaluated how body fat percentage, measured by a portable near-infrared interactance (NIR) device predicts cardiovascular (CVD), coronary heart disease (CHD), and ischemic stroke events in a prospective population-based survey. The study population consisted of 2,842 men and 3,196 women, who participated in the FINRISK'92 survey. Obesity was assessed with BMI, waist circumference, and waist-to-hip ratio (WHR) and body fat percentage measured with an NIR. Mean length of follow-up was 9 years and 3 months. In Cox proportional hazards regression analyses for men, BMI, waist circumference, and WHR as well as body fat percentage were predictors of a CVD event when adjusted for age and for major risk factors. Hazard ratio (HR) per 1 s.d. was 1.27 (95% confidence interval: 1.10-1.48) for body fat percentage, 1.30 (1.16-1.46) for BMI, and 1.31 (1.16-1.50) for waist circumference. Among women, the body fat lost its predictive power in a fully adjusted model. Body fat percentage, BMI, waist circumference, and WHR were predictors of a CHD event both among men and women, whereas body fat percentage did not predict ischemic stroke among either gender. We observed that body fat percentage measured by an NIR device was a significant predictor of CVD and CHD events among men and women, but in our population-based survey, it did not provide any additional predictive power over and above the simpler measures, such as BMI or WHR.

Letter from JAMA Internal Medicine — Waist to Hip Ratio as a Supplement to Body Mass Index—Reply

Study objective: To assess total and cause specific mortality among participants and non-participants of large population based health surveys. Design: A prospective follow up study. Baseline surveys were conducted in 1972, 1977, 1982, 1987, and 1992. Study end points were overall, cardiovascular, cancer and violent mortality, and deaths related to smoking and alcohol. Study cohorts were followed up until the end of 2000 through computerised record linkage. All analyses were adjusted for age. Setting: Finland. Participants: Participants and non-participants of five population based risk factor surveys. The samples included 54 372 men and women aged 25 to 64 years at baseline. Main results: The average participation rate was 81.7% among men and 87% among women. At eight year follow up, the non-participating men had twice and non-participating women 2.5-fold higher overall mortality than the participating men and women. Non-participants had also significantly higher cause specific mortality, except cancer and smoking related mortality among women. Relative differences in mortality were largest in violent and alcohol related deaths. Non-participants had considerably higher overall mortality than smoking participants, and their mortality was threefold compared with non-smoking participants. Conclusions: Observed differences in mortality show that health behaviour and health status substantially differ between non-participants and participants. Low participation rate may considerably bias the results of population based health surveys.

Several studies have suggested that migraine is a risk factor for stroke. The association between migraine and the risk of stroke has been observed most often among premenopausal women but also in some studies among men. The association may be stronger among women who smoke and among women using oral contraceptives compared with nonsmokers and nonusers. Classic migraine with aura may be a more powerful predictor of stroke than common migraine without aura. Findings of a recent population-based study suggest that subclinical brain lesions are more common among migraine patients, particularly among those with aura, than among the control subjects. Two cohort studies have shown that chronic non-specific headache also is related to increased stroke risk. The effect of treatment of migraine and other types of headache on the risk of stroke is not known. Even though the relative risk of stroke may be fairly high among migraine patients, the absolute risk is usually low due to low baseline risk among young people.