Table 4.

Studies of chocolate and heart failure.

Study	Design, Country	Types of participants	Number of participants	Exposure ascertainment	Outcome ascertainment	Use of adjustments	Results
Janszky 2009 [17]	Cohort study, Sweden	Non-diabetic participants post acute myocardial infarction in Stockholm Heart Epidemiology Program.	1169	Self-reported usual chocolate consumption.	Congestive heart failure events based on ICD-9 and 10 codes.	Adjusted for age, sex, smoking, obesity, physical inactivity, alcohol use, coffee intake, education and sweet score.	Congestive heart failure with less than once per month chocolate adjusted HR 0.82 (0.56–1.19), up to once per week chocolate adjusted HR 0.68 (0.47–0.97), twice or more a week chocolate adjusted HR 0.78 (0.52–1.16) compared to never consumption of chocolate.
Lewis 2010 [16]	Post-hoc analysis of RCT, Australia	Older women randomized to calcium supplementation.	1216	Chocolate consumption using validated questionnaire.	Heart failure events based on ICD-10-AM codes.	Adjusted for age, body mass index, socioeconomic status and energy intake.	Chocolate serving/week ≥1 vs <1: event rate 18/637 (2.8%) vs 35/579 (6%); adjusted OR 0.41 0.22–0.76, p = 0.01.
Mostofsky 2010 [15]	Cohort study, Sweden	Middle-aged and elderly women in Swedish Mammography Cohort.	31,823	Chocolate consumption using food frequency questionnaire.	Heart failure events based on ICD-9 and 10 codes.	Adjusted for total energy, age, education, body mass index, physical activity, smoking, living alone, postmenopausal hormone use, alcohol consumption, family history, hypertension and high cholesterol.	Chocolate vs no chocolate: 1–3 serving/month HR 0.74 (0.58–0.95), 1–2 serving/week HR 0.68 (0.50–0.93), 3–6 servings/week HR 1.09 (0.74–1.62), ≥1 serving/day HR 1.23 (0.73–2.08).
Petrone 2014 [18]	Post-hoc analysis of RCT, USA.	US male physicians who were randomized to low-dose aspirin. β-carotene, vitamin C, E and multivitamin in the Physicians' Health Study.	20,278	Chocolate consumption using food frequency questionnaire.	Heart failure based on annual follow-up questionnaires mailed to each participant and diagnoses were previously validated by reviewing medical records in a subsample.	Adjusted for age, BMI, alcohol consumption, smoking, exercise, caloric intake and prevalent atrial fibrillation.	Chocolate intake frequency and heart failure (Model 1): Never or <1/month: HR 1.00 1–3/month: HR 0.86 (0.72–1.03) 1/week: HR 0.80 (0.66–0.98) 2–4/week: HR 0.92 (0.74–1.13) 5+/week: HR 0.82 (0.63–1.07)
Current study	Cohort study, United Kingdom	General population.	20,987	Chocolate consumption based on food frequency questionnaire.	Incident heart failure events based on linkage to admissions database.	Adjusted for age, education level, social class, physical activity, smoking status, body mass index, myocardial infarction, diabetes, arrhythmia, dietary energy and alcohol consumption.	Chocolate consumption in highest vs lowest quintile: entire cohort adjusted HR 0.85 95%CI 0.71–1.05. Subgroup of women adjusted HR 0.81 (0.58–1.13) and subgroup of men adjusted HR 0.89 (0.69–1.14).