Habitual Chocolate Consumption and 24‐Hour Blood Pressure Control in Older Adults with Hypertension

To the Editor: There is evidence from randomized clinical trials that chocolate or flavanol-rich cocoa products decrease blood pressure (BP) in the short-term,1-4 and some studies suggest that this BP-lowering effect is stronger in individuals with hypertension and prehypertension.4 This is relevant because control of hypertension is still suboptimal in treated individuals 5 and especially in elderly adults,6 but it is unclear whether habitual consumption of cocoa products yields long-term BP reductions. Most research on the effect of chocolate or flavonoid-rich products on BP has relied on single measurements of BP, despite the fact that an isolated clinical BP reading may not reflect true BP.7 Also, the night-to-day ratio of BP is an important predictor of cardiovascular disease.8 Therefore, the association between habitual chocolate intake and BP control and having a blood pressure dipper pattern was assessed in a large sample of community-dwelling older adults with hypertension. This was a cross-sectional study with data obtained during follow-up of the Seniors Study on Nutrition and Cardiovascular Risk in Spain (ENRICA) cohort.9 In 2012, ambulatory blood pressure monitoring (ABPM) was performed in 1,274 subjects aged 63 and older who also underwent a telephone interview and physical examination. Information about habitual diet and chocolate consumption in the last year was assessed using a computerized dietary history.10 ABPM was performed using a validated device (WatchBP O3, Microlife Corp., Widnau, Switzerland) programmed to register BP at 20-minute intervals during the day and 30-minute intervals during the night for a 24-hour period. Valid registries had to fulfill a series of preestablished criteria, including 24-hour duration and at least 70% successful recordings of systolic BP (SBP) and diastolic BP (DBP) during the daytime and nighttime periods, or at least 20 recordings during the day and seven during the night. Night-to-day ratios for SBP and DBP were calculated, and circadian patterns were defined by calculating percentage decline in BP during the night using the formula [(daytime BP – night-time BP)/daytime BP] × 100. Participants were classified as dippers when SBP decline was 10% or greater. Ambulatory hypertension was defined as mean 24-hour BP of 130/80 mmHg or greater or being under antihypertensive treatment. Of the 1,274 individuals with 24-hour BP measurement, 1,164 provided complete information on the study variables and adhered to preestablished ABPM quality criteria; the 715 of these who had ABPM-based hypertension formed the analytical sample. Logistic regression with adjustment for potential confounders was used to calculate odds ratios (ORs) for the association between chocolate consumption and controlled 24-hour BP (<130/80 mmHg). ORs were similarly calculated for having a dipper BP pattern according to categories of chocolate consumption. Of the 715 participants, 325 (45.4%) consumed chocolate habitually (mean consumption 8.0 ± 15.2 g/d). Mean 24-hour, daytime, and nighttime SBP were 127 ± 12, 130 ± 12, and 121 ± 13 mmHg, and nocturnal decline in SBP was 6.4 ± 6.4%. Mean 24-hour, daytime, and nighttime DBP were 71 ± 7, 73 ± 8, and 66 ± 8 mmHg and nocturnal decline in DBP was 9.6 ± 8.1%. There were 393 (55.0%) participants with controlled 24-hour hypertension. The odds of having controlled BP in hypertensive individuals were similar in those consuming less than 10 g/d (OR=0.85, 95% CI=0.54–1.33) and in those consuming 10 g/d or more (OR=1.11, 95% CI=0.73–1.69) than in those consuming not chocolate (P for trend=.64) (Table 1). In addition, stratified analyses did not show differences in the association between chocolate and BP control according to age, lifestyle, and chronic diseases, although greater chocolate consumption was associated with greater probability of BP control in men (P for trend= .009), but not women. Two hundred three (28.4%) participants had a dipper pattern. No association between chocolate consumption and having a dipper BP pattern was found (<10 g/d: OR=0.85, 955 CI=0.53–1.35; ≥10 g/d: OR=1.02, 955 CI=0.66–1.56) (P for trend=.52) (Table 1). Never smokers with consumption of 10 g/d or more of chocolate had an 87% higher probability of having a dipper pattern than those who did not eat chocolate (P for trend=.04). In conclusion, these results do not support a beneficial effect of habitual consumption of small amounts of chocolate on BP in elderly adults with hypertension. The slightly beneficial effect of chocolate on 24-hour BP control in men and nonsmokers needs to be examined in further studies. Still, possible beneficial effect on BP of high amounts of cocoa, such as those tested in short-term clinical trials, cannot be excluded. Data collection was funded by Fondo de Investigaciones Sanitarias (FIS) Grants 09/1626 and 12/1166 (Ministry of Health of Spain), Grant FP7-HEALTH-2012-Proposal No: 305483–2 (FRAILOMIC Initiative), and the Cátedra de Epidemiología y Control del Riesgo Cardiovascular. Specific funding for this analysis was obtained from FIS Grants 09/104 and 13/288 (Ministry of Health of Spain). Author Contributions: Orozco-Arbeáez, Lopez-Garcia: study concept and design, statistical analyses, drafting manuscript. All authors: data analysis and interpretation, revision of manuscript for important intellectual content, approval of final version. Sponsor's Role: The study funders had no role in study design or in the collection, analysis, or interpretation of data. The authors have sole responsibility for the manuscript content.