1.
Drugs for preventing lung cancer in healthy people.
Cortés-Jofré, M, Rueda, JR, Asenjo-Lobos, C, Madrid, E, Bonfill Cosp, X
The Cochrane database of systematic reviews. 2020;(3):CD002141
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Abstract
BACKGROUND This is the second update of this Cochrane Review. Some studies have suggested a protective effect of antioxidant nutrients and higher dietary levels of fruits and vegetables on lung cancer. OBJECTIVES To determine whether vitamins and minerals and other potential agents, alone or in combination, reduce lung cancer incidence and lung cancer mortality in healthy populations. SEARCH METHODS We searched CENTRAL, MEDLINE and Embase from 1974 to May 2019 and screened references included in published studies and reviews. SELECTION CRITERIA We included randomised controlled trials (RCTs) comparing vitamins or mineral supplements with placebo, administered to healthy people with the aim of preventing lung cancer. DATA COLLECTION AND ANALYSIS Four review authors independently selected the trials to be included in the review, assessed their methodological quality and extracted data. For dichotomous outcomes we calculated risk ratios (RRs) and 95% confidence intervals (CIs) and pooled results using the random-effects model. We assessed the risk of bias using Cochrane's 'Risk of bias' assessment tool and certainty of evidence using the GRADE approach. MAIN RESULTS In this update, we identified three new trials for a total of 12 studies. Six analysed vitamin A, three vitamin C, three combined vitamin D3 + calcium, four vitamin E combined with other products, one selenium supplements and nine studied combinations of two or more products. Four studies included only men and five only women. Vitamin A results in little to no difference in lung cancer incidence (RR 1.09, 95% CI 1.00 to 1.19; 5 RCTs, 212314 participants; high-certainty evidence) and lung cancer mortality (RR 1.06, 95% CI 0.81 to 1.38; 3 RCTs, 190118 participants; high-certainty evidence). But in smokers or asbestos workers vitamin A increases the risk of lung cancer incidence (RR 1.10, 95% CI 1.01 to 1.20; 3 RCTs, 43995 participants; high-certainty evidence), lung cancer mortality (RR 1.18, 95% CI 1.01 to 1.38; 2 RCTs, 29426 participants; high-certainty evidence) and all-cause mortality (RR 1.09, 95% CI 1.05 to 1.13; 2 RCTs, 32883 participants; high-certainty evidence). Vitamin A increases the risk of minor side effects, such as yellowing of the skin and minor gastrointestinal symptoms (high-certainty evidence). Vitamin C likely results in little to no difference in lung cancer incidence (RR 1.29, 95% CI 0.67 to 2.49; 2 RCTs, 14953 participants; moderate-certainty evidence). In women, vitamin C increases the risk of lung cancer incidence (RR 1.84, 95% CI 1.14 to 2.95; 1 RCT, 7627 participants; high-certainty evidence). In men, vitamin C results in little to no difference in mortality for lung cancer (RR 0.81, 95% CI 0.53 to 1.23; 1 RCT, 7326 participants; high-certainty evidence). Vitamin D + calcium may result in little to no difference in lung cancer incidence in postmenopausal women (RR 0.90, 95% CI 0.39 to 2.08; 3 RCTs, 37601 women; low-certainty evidence). Vitamin E results in little to no difference in lung cancer incidence (RR 1.01, 95% CI 0.90 to 1.14; 3 RCTs, 36841 participants; high-certainty evidence) or to lung cancer mortality (RR 0.96, 95% CI 0.77 to 1.18; 2 RCTs, 29214 participants; high-certainty evidence), but increases the risk of haemorrhagic strokes (hazard ratio (HR), 1.74, 95% CI 1.04 to 2.91; 1 RCT, 14641 participants; high-certainty evidence). Calcium results in little to no difference in lung cancer incidence in postmenopausal women (RR 0.65, 95% CI 0.13 to 3.18; 1 RCT, 733 participants) or in risk of renal calculi (RR 1.94, 95% CI 0.20 to 18.57; 1 RCT, 733 participants; low-certainty evidence). Selenium in men results in little to no difference in lung cancer incidence (RR 1.11, 95% CI 0.80 to 1.54; 1 RCT, 17448 participants; high-certainty evidence) and lung cancer mortality (RR 1.09, 95% CI 0.72 to 1.66; 1 RCT, 17448 participants; high-certainty evidence) and increases the risk for grade 1 to 2 dermatitis (RR 1.16, 95% CI 1.04 to 1.31; 1 RCT, 17448 participants; high-certainty evidence) and for alopecia (RR 1.28, 95% CI 1.07 to 1.53; 1 RCT, 17448 participants; high-certainty evidence). The combination of vitamins A, C, E + selenium + zinc results in little to no difference in lung cancer incidence (RR 0.64, 95% CI 0.28 to 1.48; 1 RCT, 12741 participants; high-certainty evidence). AUTHORS' CONCLUSIONS Well-designed RCTs have shown no beneficial effect of supplements for the prevention of lung cancer and lung cancer mortality in healthy people. Vitamin A supplements increase lung cancer incidence and mortality in smokers or persons exposed to asbestos. Vitamin C increases lung cancer incidence in women. Vitamin E increases the risk of haemorrhagic strokes.
2.
Vitamins and Minerals for Migraine Prophylaxis: A Systematic Review and Meta-analysis.
Okoli, GN, Rabbani, R, Kashani, HH, Wierzbowski, AK, Neilson, C, Mansouri, B, Zarychanski, R, Abou-Setta, AM
The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques. 2019;(2):224-233
Abstract
OBJECTIVE To summarize the findings of randomized controlled trials (RCTs) on the efficacy and safety of vitamins and minerals for migraine prophylaxis. METHODS We systematically searched bibliographic databases and relevant websites for parallel and crossover RCTs reporting efficacy and/or safety of vitamins and/or minerals for migraine prophylaxis. Our primary outcomes were migraine frequency (number of attacks) and duration (hours). Secondary outcomes were severity (intensity), days with migraine, and adverse events. Meta-analysis was conducted when analyzable data were available from at least two trials. RESULTS Eighteen placebo-controlled trials met our eligibility criteria. Only coenzyme Q10 and magnesium contributed to meta-analyses. In adults, compared with placebo, coenzyme Q10 did not significantly decrease migraine frequency (mean difference (MD) -0.44 (-2.14 to 1.26); I2 53%; 2 trials; 97 participants; moderate strength of the evidence), duration (MD -1.97 (-4.82 to 0.87); I2 0%; 2 trials; 97 participants; moderate strength of the evidence), or severity (ratio of means (RoM) -0.05 (-0.20 to 0.11); I2 0%; 2 trials; 97 participants). In adults, compared with placebo, magnesium did not significantly decrease migraine severity (RoM -0.17 (-0.36 to 0.02); I2 48%; 3 trials; 226 participants; low strength of the evidence). Meta-analysis of other vitamins and minerals, and other outcomes were not feasible due to a lack of sufficiently reported data. CONCLUSIONS Based on insufficient evidence, it is unknown if coenzyme Q10 and magnesium are effective for migraine prophylaxis in adults. High-quality, adequately powered RCTs are needed to fully evaluate the efficacy and safety of vitamins and minerals for migraine prophylaxis.