This study investigated whether sensitivity of the nocturnal melatonin suppression response to light depends on the area of the retina exposed. The reason to suspect uneven spatial sensitivity distribution stems from animal work that revealed that retinal ganglion cells projecting to the suprachiasmatic nuclei (SCN) are unequally distributed in several species of mammals. Four distinct areas of the retinas of 8 volunteers were selectively exposed to 500 lux between 1:30 a.m. and 3:30 a.m. Saliva samples were taken before, during, and after light exposure in 1-h intervals. A significant difference in sensitivity was found between exposure of the lateral and nasal parts of the retinas, showing that melatonin suppression is maximal on exposure of the nasal part of the retina. The results imply that artificial manipulation of the circadian pacemaker to alleviate jet lag, to improve alertness in shift workers, and possibly to treat patients suffering from seasonal affective disorder should encompass light exposure of the nasal retina.
Background: Insufficient serum vitamin D concentrations (50–75 nmol/L) are prevalent in 40–65% of patients who require total hip arthroplasty (THA). This could impair physical recovery after surgery. This study investigated the association between preoperative vitamin D status and physical performance after THA. Additionally, postoperative changes in vitamin D concentrations were measured. Methods: We included 87 patients scheduled for elective THA and aged ≥65 years. Three groups were recruited: patients classified as vitamin D deficient (< 50 nmol/L, n = 23), insufficient (50–75 nmol/L, n = 32), or sufficient (> 75 nmol/L, n = 32). Serum 25-hydroxyvitamin D3 (25[OH]D3) concentration and physical performance were measured perioperatively. Linear mixed models were used to examine differences between groups. Results: Change in physical performance over time was not affected by preoperative vitamin D status. In contrast, for physical activity, both vitamin D (p = 0.021) and time (p < 0.001) effect was seen: from 80.2 ± 25.8 to 58.1 ± 17.8 min/day in the deficient group, 143.7 ± 19.8 to 92.9 ± 11.5 min/day in the insufficient group, and 108.1 ± 20.9 to 62.3 ± 12.9 min/day in the sufficient group. The Chair Stand Test, Timed Up and Go test, and 10-Meter Walking Test also improved significantly over time, but independent of vitamin D status. An increase in 25(OH)D3 concentration 6 weeks postoperatively was correlated with improved hip function (Pearson’s r = –0.471, p = 0.018). Overall, serum 25(OH)D3 declined with 32% one day after surgery (p < 0.001), to nearly return to baseline values 6 weeks later in all groups. Conclusion: Vitamin D status did not appear to affect physical recovery after THA. The drop in vitamin D after surgery deserves further investigation, but could possibly be explained by hemodilution.
Scope: Coffee is associated with a lower risk of cancer, cardiovascular disease, and type 2 diabetes at the population level. However, individual susceptibility to the effects of coffee consumption will cause heterogeneity in health responses between individuals. In this critical review determinants of inter-individual variability in cancer and cardiometabolic health outcomes in response to coffee and caffeine consumption are systematically evaluated. Methods and results: Embase and MEDLINE are searched for observational studies and clinical trials that examined variation in the response to coffee consumption. A total of 74 studies meet the inclusion criteria, which report variation in cancer (n = 24) and cardiometabolic health (n = 50) outcomes. The qualitative analysis shows that sex, BMI, smoking, alcohol intake, menopausal status, and genetic polymorphisms are probable or possible determinants of inter-individual variability in cancer and cardiometabolic health outcomes in response to coffee and caffeine consumption, albeit the majority of studies have insufficient statistical power to detect significant interaction between these factors and coffee consumption. Conclusion: Several genetic and non-genetic determinants of inter-individual variability in the responses to coffee and caffeine consumption are identified, indicating that some of the health benefits of coffee may only occur in a subgroup of subjects.
Purpose Dietary factors have been suggested as drivers of the rising prevalence of adult-onset asthma, but evidence is inconclusive, possibly due to the complex interrelation with obesity. We aim to explore the relation of diet quality and food intake with incident adult-onset asthma in normal weight and overweight adults of the prospective population-based Lifelines Cohort Study. Methods Incident adult-onset asthma was defined as self-reported asthma at ± 4-year follow-up, in adults free of airway disease at baseline. Diet quality scores and food group intake were assessed at baseline. Log-binomial regression analyses were used to estimate adjusted relative risks (RR) between dietary intake (per portion) and incident adult-onset asthma, in categories of BMI (cutoff: 25 kg/m2). Results 477 incident asthma cases (75% female, 62% overweight) and 34,698 controls (60% female, 53% overweight) were identified. Diet quality—assessed by the Lifelines Diet Score and Mediterranean Diet Score—was not associated with incident adult-onset asthma in the two BMI groups. Although the dietary intake of several food groups differed between cases and controls, after adjustment for confounders only few remained associated with adult-onset asthma, including red and processed meat (RR: 0.93 per 15 g intake; 95% CI 0.86–0.99) in the normal weight group and intake of cheese (RR 1.09 per 20 g intake; 95% CI 1.00–1.17) and vegetables (RR 1.10 per 50 g intake; 95% CI 1.00–1.21) in the overweight group. Conclusion The results of this study question the role of food as a ‘simple’ predictor of adult-onset asthma and call for an integrative approach, including a range of modifiable lifestyle factors and further asthma phenotyping.
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