Table 4.
Studies investigating iodine among vegans, vegetarians, and omnivores in industrialised countries.
| Study, Year | Study Design | Location | Dietary Groups | Sample (n) (Male, Female) | Method of Dietary Classification | Average Diet Adherence (Years) |
|---|---|---|---|---|---|---|
| Alles, 2017 [36] | Cross-Sectional | France | Vegan | 789 | Assessed by investigators pre-study | NA |
| Vegetarian | 2370 | |||||
| Omnivore | 90,664 | |||||
| Draper, 1993 [37] | Cross-sectional | London, UK | Vegan | 38 (18,20) | Self-reported | 1.0 |
| Lacto-Vegetarian | 52 (16,36) | 2.0 | ||||
| Demi-vegetarian | 37 (13,24) | 5.0–9.0 | ||||
| Elorinne, 2016 [48] | Matched pairs by age and sex | Kuopio, Finland | Vegan | 22 (16,6) | Self-reported | 8.6 |
| Omnivore | 19 (11,8) | NA | ||||
| Henjum, 2018 [38] | Cross-Sectional | Norway, eastern and western geographical regions | Vegan | 27 | Self-reported | NA |
| Vegetarian | 9 | |||||
| Omnivore | 367 | |||||
| Kristensen, 2015 [49] | Matched pairs by age | Denmark | Vegan | 75 (36,39) | Self-reported | ≤1.0 |
| Omnivore | 1627 (716, 911) | NA | ||||
| Krajcovicová-Kudlácková, 2003 [39] | Cross-sectional | Slovakia | Vegan | 15 (6,9) | Self-reported | 9.7 |
| Vegetarian | 31 (12,19) | 9.0 | ||||
| Omnivore (Mixed Diet) | 35 (15,20) | NA | ||||
| Leung, 2011 [40] | Cross-sectional | Boston, Massachusetts | Vegan | 63 | Self-reported | 11.3 ± 11.7 1 |
| Vegetarian | 78 | 5.6 ± 5.7 1 | ||||
| Lightowler, 1998 [41] | Cross-sectional | London and surrounding counties, UK | Vegan | 30 (11,19) | Self-reported | M, 10.0, F, 9.2 |
| Lightowler, 2002 [42] | Cross-sectional | London and the south-east of England, UK | Vegan | 26 (11, 15) | Self-reported | M, 9.9, F, 11.7 |
| Nebl, 2019 [43] | Cross-sectional | Hanover, Germany | Vegan | 27 (11,16) | Assessed by investigators pre-study | >2.0 |
| Vegetarian | 25 (10, 15) | >2.0 | ||||
| Omnivore | 27 (10,17) | >3.0 | ||||
| Rauma, 1994 [50] | Matched pairs | Kuopio, Finland. | Vegan (Living Food Diet) | 12 | Self-reported | 6.7 ± 3.8 1 |
| Omnivore | 12 | NA | ||||
| Remer, 1999 [47] | Repeated-measures | Germany | Vegetarian (Lacto) | 6 (3,3) | Allocated by investigators | 0.0 |
| Omnivore | 6 (3,3) | |||||
| Omnivore (High protein) | 6 (3,3) | |||||
| Schüpbach, 2017 [44] | Cross-sectional | Lausanne and Zurich, Switzerland | Vegan | 53 (20,33) | Self-reported | ≤1.0 |
| Vegetarian | 53 (17,36) | ≤1.0 | ||||
| Omnivore | 100 (37,63) | ≤1.0 | ||||
| Sobiecki, 2016 [45] | Cross-sectional | Oxford, UK | Vegan | 803 | Assessed by investigators pre-study | ≤1.0 |
| Vegetarian | 6673 | ≤1.0 | ||||
| Pescatarian | 4531 | ≤1.0 | ||||
| Omnivore (Meat-eaters) | 18,244 | ≤1.0 | ||||
| Waldmann, 2003 [46] | Cross-sectional | Hanover, Germany | Vegan (Strict) | 98 | Assessed by investigators pre-study | 4.3 |
| Vegan (Moderate) | 56 | 3.4 |
NA, not assessed; M, male; F, female; 1, mean ± SD.