Cardiovascular symptoms affect the patterns of habitual coffee consumption.

BACKGROUND: Excessive coffee consumption can lead to unpleasant sensations such as tachycardia and heart palpitations. OBJECTIVES: Our aim was to investigate if cardiovascular symptoms can lead to alterations in habitual patterns of coffee consumption. METHODS: We used information from up to 390,435 European ancestry participants in the UK Biobank, aged 39-73 y. Habitual coffee consumption was self-reported, and systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate were measured at baseline. Cardiovascular symptoms at baseline were based on hospital diagnoses, primary care records, and/or self-report. Mendelian randomization (MR) was used to examine genetic evidence for a causal association between SBP, DBP, and heart rate with habitual coffee consumption. RESULTS: Participants with essential hypertension, angina, or heart arrhythmia were all more likely to drink less caffeinated coffee and to be non-habitual or decaffeinated coffee drinkers compared with those who did not report related symptoms (P ≤ 3.5 × 10-8 for all comparisons). Higher SBP and DBP were associated with lower caffeinated coffee consumption at baseline, with consistent genetic evidence to support a causal explanation across all methods [MR-Egger regression (MREggr) ß: -0.21 cups/d (95% CI: -0.34, -0.07) per 10 mm Hg higher SBP and -0.33 (-0.61, -0.07) per 10 mm Hg higher DBP)]. In genetic analyses, higher resting heart rate was associated with a greater odds of being a decaffeinated coffee drinker (MREggr OR: 1.71; 95% CI: 1.31, 2.21) per 10 beats/min). CONCLUSIONS: We provide causal genetic evidence for cardiovascular system-driven influences on habitual coffee intakes, suggesting that people tend to naturally regulate their coffee consumption based on blood pressure levels and heart rate. These findings suggest that observational studies of habitual coffee intakes are prone to influences by reverse causation, and caution is required when inferred health benefits result from comparisons with coffee abstainers or decaffeinated coffee drinkers.

Associations of depressive symptoms and history with three a priori diet quality indices in middle-aged and older adults.

BACKGROUND: Evidence for the diet-depression link is growing but longitudinal studies on the reverse association are scarce. We investigated associations of (1) current depressive symptoms, (2) short-term changes in and (3) long-term history of depressive symptoms with three a priori diet quality indices. METHODS: Data were from participants (≥ 55 years) of the Longitudinal Aging Study Amsterdam (LASA). The Mediterranean Diet Score (MDS), Alternative Healthy Eating Index (AHEI-2010) and Dietary Approaches to Stop Hypertension diet (DASH) were derived in 2014/2015. Depressive symptoms (Center for Epidemiologic Studies Depression scale; CES-D) were assessed in 2014/2015 and at five regular 3-yearly cycles from 2001-2003 to 2015/2016. Associations between three depression determinants and the diet indices were analysed by multivariable linear regression models. RESULTS: Cross-sectionally (n = 1312), current depressive symptoms (CES-D ≥ 16) were associated with lower MDS (adjusted B = -1.21, 95%CI = -2.41, -0.023) and AHEI (B = -2.72, 95%CI = -5.24, -0.20) scores in men only. Chronic/recurrent depressive symptoms (CES-D ≥ 16 in both 2011-2013 and 2015/2016) were associated with lower MDS scores (n = 1233; B = -2.22, 95%CI = -3.40, -1.04) and a trend for lower AHEI scores (B = -2.37, 95%CI = -4.92, 0.18), compared to no depressive symptoms (twice CES-D < 16). History of depressive symptoms (ever CES-D ≥ 16 from 2001-2003 to 2011-2013; n = 687) was associated with lower MDS (B = -1.87, 95%CI = -3.47, -0.27) and AHEI (B = -4.33, 95%CI = -7.54, -1.13) scores in men only. No associations were found with the DASH score. LIMITATIONS: Single dietary data collection impeded investigation of prospective depression-diet associations. CONCLUSIONS: Our study in middle-aged and older adults suggests that current and past depressive symptoms are associated with poorer diet quality, particularly in men.

RCTS are the only appropriate way to demonstrate the role of vitamin D in health.

Despite thousands of vitamin D studies published, including hundreds of reviews and meta-analyses, it is still uncertain if supplementation with vitamin D will have positive health effects, except for the skeleton. This cannot be answered by doing more observational studies as it is impossible to control for confounding factors and reverse causality. The only way to firmly prove positive vitamin D effects is by doing the properly designed randomized controlled trials (RCTs). However, it has been difficult to show the expected positive effects by vitamin D supplementation in RCTs, which may indicate that the effects, if present must be small. On the other hand, results from Mendelian randomization studies have shown promising results at least for mortality and multiple sclerosis. In the near future, results from several large RCTs with hard endpoints will be available. If these show positive results, the main question on vitamin D and health is answered. If they turn out negative, they will be criticized for having included subjects without vitamin D deficiency, and some studies might not have used an optimal dosing regimen. New and better-designed RCTs will then be needed, but will be very hard to perform.

Following the World Health Organization's Recommendation of Exclusive Breastfeeding to 6 Months of Age Does Not Impact the Growth of Rural Gambian Infants.

BACKGROUND: The WHO recommends exclusive breastfeeding (EBF) for the first 6 mo of life. OBJECTIVE: The objective of this study was to assess the benefit of EBF to age 6 mo on growth in a large sample of rural Gambian infants at high risk of undernutrition. METHODS: Infants with growth monitoring from birth to 2 y of age (n = 756) from the ENID (Early Nutrition and Immune Development) trial were categorized as exclusively breastfed if only breast milk and no other liquids or foods were given. EBF status was entered into confounder-adjusted multilevel models to test associations with growth trajectories by using >11,000 weight-for-age (WAZ), length-for-age (LAZ), and weight-for-length (WLZ) z score observations. RESULTS: Thirty-two percent of infants were exclusively breastfed to age 6 mo. The mean age of discontinuation of EBF was 5.2 mo, and growth faltering started at ∼3.5 mo of age. Some evidence for a difference in WAZ and WHZ was found between infants who were exclusively breastfed to age 6 mo (EBF-6) and those who were not (nEBF-6), at 6 and 12 mo of age, with EBF-6 children having a higher mean z score. The differences in z scores between the 2 groups were small in magnitude (at 6 mo of age: 0.147 WAZ; 95% CI: -0.001, 0.293 WAZ; 0.189 WHZ; 95% CI: 0.038, 0.341 WHZ). No evidence for a difference between EBF-6 and nEBF-6 infants was observed for LAZ at any time point (6, 12, and 24 mo of age). Furthermore, a higher mean WLZ at 3 mo of age was associated with a subsequent higher mean age at discontinuation of EBF, which implied reverse causality in this setting (coefficient: 0.060; 95% CI: 0.008, 0.120). CONCLUSION: This study suggests that EBF to age 6 mo has limited benefit to the growth of rural Gambian infants. This trial was registered at http://www.isrctn.com as ISRCTN49285450.