The primary strengths of a cross-sectional Kuwaiti study were recruitment of a large, randomly selected sample using trained, multilingual researchers conducting computer-aided phone interviews. The questionnaire was developed based on existing questionnaires used in previous studies for gathering dietary supplement consumption and lifestyle information , . In a second prospective cohort study, Diet, Cancer, and Health Study, 55,543 Danish adults (age 50-64 years) were asked about 55 lifestyle, dietary, and supplement consumption practices in the preceding 12 months (125) at baseline. In the Swedish Male Cohort Study, self-reported use of the mono-nutrient vitamin C supplement (taken seven times or more a week) at baseline was associated with a 2-fold increased risk of developing renal stones in 48,840 men (ages 45-79 years) followed over an 11-year period.
In 2004, a combined analysis of nine prospective cohort studies found that intake of dietary vitamin C supplements (>=400 mg/day over a mean 10-year period) was negatively associated with risk for CHD, but dietary vitamin C intake was not. A meta-analysis of observational studies found reduced age-related cataract risk with higher dietary vitamin C intake in case-control studies and higher blood concentrations of vitamin C in cross-sectional studies. By combining data from 13 prospective cohort studies comprising 676,141 participants, it was determined that vitamin C intake by diet was unrelated to colon cancer, whereas the total intake of vitamin C (i.e., derived from foods and supplements) was associated with 19% reduced risk of colon cancer.
Recent data provided by Bailey et al., which estimated the dietary intake in the US population using the 2003-2006 NHANES, showed that the proportion of dietary supplements used was 26 percent in adolescents aged 14-18 years, while it was higher (43%) in children aged 4-8 years . We found that 35% of surveyed adolescents used dietary supplements; our findings are similar to data reported in a Korean study, which reported 31% of students attending a secondary school used dietary supplements, and data from NHANES 1999-2000, which showed dietary supplement use prevalence was 27.4% and 32.4%, respectively, in 16-19 year-old men and women. Nearly a quarter (23%) of Lebanese adults reported current consumption of vitamins and/or mineral supplements, while 18% consumed herbal supplements.
Ref. The steady trend of total supplement consumption is at odds with earlier studies reporting an increase in their consumption during the 1980s to the early 2000s. With the current data, it is evident that the consumption of supplements has leveled off among U.S. adults. A recent serial cross-sectional study using nationally representative NHANES data (n=37,958) collected from 1999-2012 found that use of supplements was steady between 1999 and 2012, with 52% of adults reporting using some form of supplements in 2011-2012 . Results In this serial cross-sectional study among 37 958 adults using the nationally representative National Health and Nutrition Examination Survey, self-reported use of any supplements remained stable, with 52 % reporting use in both 1999-2012 and 2011-2012.
Findings In this serial cross-sectional study of 37 958 adults using the nationally representative National Health and Nutrition Examination Survey 37 958 adults the nationally representative National Health and Nutrition Examination Survey, self-reported use of any supplement products remained stable, with 52 % reporting use in both 1999-2012 and 2011-2012. Using data from the National Health and Nutrition Examination Survey (NHANES), the present study was designed to quantify trends in the use of supplements in U.S. adults between 1999-2000 and 2011-2012, focusing specifically on the use of all-purpose and MVMM, defined as use of all products that contained 10 or more vitamins/minerals, and the use of separate vitamins, minerals, and nonvitamins, nonminerals (NVNM) products. Fifth, a sequential, cross-sectional study design precluded longitudinal measures of supplement use among the same individuals. The use of multiple-choice items may have prevented collection of additional information on supplement use within the Italian population.
That is, the majority of participants expressed a belief that the reporting system would have been useful. The published literature has identified an increased risk for adverse events associated with the use of H.S., particularly with herbal supplements, because there is an increased possibility of their contamination with, for instance, heavy metals and pesticide residues. In 2014, a cross-sectional study using a random sample of US Royal Navy and Marine Corps personnel (n=1,708) reported that 29% of the users of HS (dietary/dietary supplements) reported at least one adverse event during the preceding six-month period . The authors stressed that the benefits demonstrated in the clinical trial of REDUCE-IT should not be transferred to all omega-3 products, particularly to dietary supplements, because of differences between the supplement ingredients and those used in their studies .
The available studies that assessed meningioma HRQoL used various different instruments, none of which were designed or tested exclusively on meningioma patients. When searching for randomised trials on humans, validated filters should be used to identify studies of the appropriate designs. However, CENTRAL is designed to only include reports of studies designs that are likely relevant to Cochrane Review inclusion, and therefore searches on CENTRAL should either not use the trials filter, or should restrict themselves to studies with humans.
For most sources listed in Section 4.3, the search procedure will extract single reports of studies, so that multiple reports of the same study will have to be identified and linked manually by review authors. However, an increasing number of sources are available that are based on studies, linking multiple reports of the same study together, such as Cochrane Registry of Research and specialized registers for a range of CRGs and fields (see Online Technical Supplement), as well as a few more trials registries and regulatory and industry sources. Discussion The findings in the current study offer an understanding of the intake of food additives in the Italian youth, which highlights the need for fostering additional awareness in adolescents regarding appropriate dietary supplement use, particularly regarding indications and contraindications.