body mass index

Importance  Epidemiologic and trial data suggest that vitamin D supplementation may reduce metastatic cancer and cancer mortality, reflecting shared biological pathways.

Objective  To follow up on the possible reduction in cancer death in the Vitamin D and Omega-3 Trial (VITAL) with an evaluation of whether vitamin D reduces the incidence of advanced (metastatic or fatal) cancer and an examination possible effect modification by body mass index.

Design, Setting, and Participants  VITAL is a randomized, double-blind, placebo-controlled, 2 × 2 factorial clinical trial of vitamin D3 (cholecalciferol, 2000 IU/d) and marine omega-3 fatty acids (1 g/d). This multicenter clinical trial was conducted in the United States; participants included men aged 50 years or older and women aged 55 years or older who were free of cancer and cardiovascular disease at baseline. Randomization took place from November 2011 through March 2014, and study medication ended on December 31, 2017. Data for this secondary analysis were analyzed from November 1, 2011, to December 31, 2017.

Interventions  Vitamin D3 (cholecalciferol, 2000 IU/d) and marine omega-3 fatty acids (1 g/d) supplements.

Main Outcomes and Measures  For the present analysis, the primary outcome was a composite incidence of metastatic and fatal invasive total cancer, because the main VITAL study showed a possible reduction in fatal cancer with vitamin D supplementation and effect modification by body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) for total cancer incidence reduction for individuals with normal BMI, but not for individuals with overweight or obesity. Secondary analyses included examination of BMI (<25, 25 to < 30, and ≥30) as effect modifiers of the observed associations.

Results  Among 25 871 randomized VITAL participants (51% female; mean [SD] age, 67.1 [7.1] years), 1617 were diagnosed with invasive cancer over a median intervention period of 5.3 years (range, 3.8-6.1 years). As previously reported, no significant differences for cancer incidence by treatment arm were observed. However, a significant reduction in advanced cancers (metastatic or fatal) was found for those randomized to vitamin D compared with placebo (226 of 12 927 assigned to vitamin D [1.7%] and 274 of 12 944 assigned to placebo [2.1%]; HR, 0.83 [95% CI, 0.69-0.99]; P = .04). When stratified by BMI, there was a significant reduction for the vitamin D arm in incident metastatic or fatal cancer among those with normal BMI (BMI<25: HR, 0.62 [95% CI, 0.45-0.86]) but not among those with overweight or obesity (BMI 25-<30: HR, 0.89 [95% CI, 0.68-1.17]; BMI≥30: HR, 1.05 [95% CI, 0.74-1.49]) (P = .03 for interaction by BMI).

Conclusions and Relevance  In this randomized clinical trial, supplementation with vitamin D reduced the incidence of advanced (metastatic or fatal) cancer in the overall cohort, with the strongest risk reduction seen in individuals with normal weight.

Trial Registration  ClinicalTrials.gov Identifier: NCT01169259

Abstract

Background: Reducing saturated fat reduces serum cholesterol, but effects on other intermediate outcomes may be less clear. Additionally, it is unclear whether the energy from saturated fats eliminated from the diet are more helpfully replaced by polyunsaturated fats, monounsaturated fats, carbohydrate or protein.

Objectives: To assess the effect of reducing saturated fat intake and replacing it with carbohydrate (CHO), polyunsaturated (PUFA), monounsaturated fat (MUFA) and/or protein on mortality and cardiovascular morbidity, using all available randomised clinical trials.

Search methods: We updated our searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid) and Embase (Ovid) on 15 October 2019, and searched Clinicaltrials.gov and WHO International Clinical Trials Registry Platform (ICTRP) on 17 October 2019.

Selection criteria: Included trials fulfilled the following criteria: 1) randomised; 2) intention to reduce saturated fat intake OR intention to alter dietary fats and achieving a reduction in saturated fat; 3) compared with higher saturated fat intake or usual diet; 4) not multifactorial; 5) in adult humans with or without cardiovascular disease (but not acutely ill, pregnant or breastfeeding); 6) intervention duration at least 24 months; 7) mortality or cardiovascular morbidity data available.

Data collection and analysis: Two review authors independently assessed inclusion, extracted study data and assessed risk of bias. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity analyses, funnel plots and GRADE assessment.

Main results: We included 15 randomised controlled trials (RCTs) (16 comparisons, ~59,000 participants), that used a variety of interventions from providing all food to advice on reducing saturated fat. The included long-term trials suggested that reducing dietary saturated fat reduced the risk of combined cardiovascular events by 21% (risk ratio (RR) 0.79; 95% confidence interval (CI) 0.66 to 0.93, 11 trials, 53,300 participants of whom 8% had a cardiovascular event, I² = 65%, GRADE moderate-quality evidence). Meta-regression suggested that greater reductions in saturated fat (reflected in greater reductions in serum cholesterol) resulted in greater reductions in risk of CVD events, explaining most heterogeneity between trials. The number needed to treat for an additional beneficial outcome (NNTB) was 56 in primary prevention trials, so 56 people need to reduce their saturated fat intake for ~four years for one person to avoid experiencing a CVD event. In secondary prevention trials, the NNTB was 32. Subgrouping did not suggest significant differences between replacement of saturated fat calories with polyunsaturated fat or carbohydrate, and data on replacement with monounsaturated fat and protein was very limited. We found little or no effect of reducing saturated fat on all-cause mortality (RR 0.96; 95% CI 0.90 to 1.03; 11 trials, 55,858 participants) or cardiovascular mortality (RR 0.95; 95% CI 0.80 to 1.12, 10 trials, 53,421 participants), both with GRADE moderate-quality evidence. There was little or no effect of reducing saturated fats on non-fatal myocardial infarction (RR 0.97, 95% CI 0.87 to 1.07) or CHD mortality (RR 0.97, 95% CI 0.82 to 1.16, both low-quality evidence), but effects on total (fatal or non-fatal) myocardial infarction, stroke and CHD events (fatal or non-fatal) were all unclear as the evidence was of very low quality. There was little or no effect on cancer mortality, cancer diagnoses, diabetes diagnosis, HDL cholesterol, serum triglycerides or blood pressure, and small reductions in weight, serum total cholesterol, LDL cholesterol and BMI. There was no evidence of harmful effects of reducing saturated fat intakes.

Authors' conclusions: The findings of this updated review suggest that reducing saturated fat intake for at least two years causes a potentially important reduction in combined cardiovascular events. Replacing the energy from saturated fat with polyunsaturated fat or carbohydrate appear to be useful strategies, while effects of replacement with monounsaturated fat are unclear. The reduction in combined cardiovascular events resulting from reducing saturated fat did not alter by study duration, sex or baseline level of cardiovascular risk, but greater reduction in saturated fat caused greater reductions in cardiovascular events.

Trial registration: ClinicalTrials.gov NCT00000611 NCT02062424 NCT00692536 NCT01954472NCT01005498 NCT01634841 NCT03354377.

Background: Obesity is a chronic disease with limited treatment options in pediatric patients. Liraglutide may be useful for weight management in adolescents with obesity.

Methods: In this randomized, double-blind trial, which consisted of a 56-week treatment period and a 26-week follow-up period, we enrolled adolescents (12 to <18 years of age) with obesity and a poor response to lifestyle therapy alone. Participants were randomly assigned (1:1) to receive either liraglutide (3.0 mg) or placebo subcutaneously once daily, in addition to lifestyle therapy. The primary end point was the change from baseline in the body-mass index (BMI; the weight in kilograms divided by the square of the height in meters) standard-deviation score at week 56.

Results: A total of 125 participants were assigned to the liraglutide group and 126 to the placebo group. Liraglutide was superior to placebo with regard to the change from baseline in the BMI standard-deviation score at week 56 (estimated difference, -0.22; 95% confidence interval [CI], -0.37 to -0.08; P = 0.002). A reduction in BMI of at least 5% was observed in 51 of 113 participants in the liraglutide group and in 20 of 105 participants in the placebo group (estimated percentage, 43.3% vs. 18.7%), and a reduction in BMI of at least 10% was observed in 33 and 9, respectively (estimated percentage, 26.1% vs. 8.1%). A greater reduction was observed with liraglutide than with placebo for BMI (estimated difference, -4.64 percentage points) and for body weight (estimated difference, -4.50 kg [for absolute change] and -5.01 percentage points [for relative change]). After discontinuation, a greater increase in the BMI standard-deviation score was observed with liraglutide than with placebo (estimated difference, 0.15; 95% CI, 0.07 to 0.23). More participants in the liraglutide group than in the placebo group had gastrointestinal adverse events (81 of 125 [64.8%] vs. 46 of 126 [36.5%]) and adverse events that led to discontinuation of the trial treatment (13 [10.4%] vs. 0). Few participants in either group had serious adverse events (3 [2.4%] vs. 5 [4.0%]). One suicide, which occurred in the liraglutide group, was assessed by the investigator as unlikely to be related to the trial treatment.

Conclusions: In adolescents with obesity, the use of liraglutide (3.0 mg) plus lifestyle therapy led to a significantly greater reduction in the BMI standard-deviation score than placebo plus lifestyle therapy. (Funded by Novo Nordisk; NN8022-4180 ClinicalTrials.gov number, NCT02918279.).

No abstract available.