Table 1.
General characteristics of systematic reviews
| Number of reviews (%) N=150 |
|
| Journal | |
| General nutrition journal (journals with only a nutrition focus) (eg, American Journal of Clinical Nutrition) | 61 (40.7%) |
| Specialised nutrition journal (journals with a focus on nutrition and a specific disease area) (eg, Nutrition, Metabolism and Cardiovascular Diseases) | 7 (4.7%) |
| General medical journal (eg, Lancet) | 28 (18.7%) |
| Specialised medical journal (eg, Clinical Breast Cancer) | 54 (36%) |
| Country of corresponding author’s affiliation | |
| North America | 14 (9.3%) |
| Europe | 43 (28.7%) |
| Oceania | 13 (8.7%) |
| Middle East | 28 (18.7%) |
| Asia | 49 (32.7%) |
| South America | 3 (0.7%) |
| Was the review conducted to inform a particular guideline or policy decision or to fulfil the needs of a particular evidence user? | |
| Yes | 6 (4%) |
| No | 144 (96%) |
| Funding* | |
| Government support | 56 (37.3%) |
| Institutional support | 34 (22.7%) |
| Private not-for-profit foundation | 20 (13.3%) |
| Food marketing/advocacy organisations | 4 (3.3%) |
| Food companies | 2 (1.3%) |
| No funding | 32 (21.3%) |
| Not reported | 34 (22.7%) |
| Did the authors declare any conflicts of interest? | |
| Yes | 10 (6.7%) |
| No | 135 (90%) |
| Not reported | 5 (3.3%) |
| Exposure(s)* | |
| Micronutrient | 27 (18%) |
| Macronutrient | 24 (16%) |
| Bioactive compounds | 15 (10%) |
| Food or beverage | 60 (40%) |
| Food group | 21 (14.0%) |
| Dietary pattern | 49 (32.7%) |
| Non-nutritive components of foods/beverages | 25 (18.7%) |
| Outcome(s)* | |
| Cardiometabolic morbidity or mortality | 26 (17.3%) |
| Cancer morbidity or mortality | 54 (36%) |
| Diseases of the digestive system | 10 (6.7%) |
| All-cause mortality | 9 (6%) |
| Anthropometric measures | 8 (5.33%) |
| Surrogate outcomes | 17 (11.3%) |
| Other | 55 (36.7%) |
| Eligible study designs* | |
| Cohort | 146 (97.3%) |
| Case-control | 97 (64.7%) |
| Cross-sectional | 80 (53.3%) |
| Randomised controlled trials | 74 (49.3%) |
| Median no of primary studies (IQR) | 15 (11 to 23) |
| Median no of participants (IQR) | 208 117 (84 951 to 510 954) |
| Method for the synthesis of results | |
| Meta-analysis | 115 (76.7%) |
| Narrative | 21 (14%) |
| Tabular/graphical summary of quantitative results without meta-analysis | 14 (9.3%) |
| Did the review assess risk of bias? | |
| Yes | 131 (87.3%) |
| No | 19 (12.6%) |
*Each review can be classified in more than one category.