Table 2 . Randomized trials of Zn and esophageal cancer .
| Author | Year | country | population | men | Mean age | Zn form (dose mg) | Other vitamins or minerals combined with Zinc | No of subjects | Factorial design | Placebo controlled/ Double blind |
Intervention
period |
Follow up
After trial |
Outcomes | Relative risk | Quality score 1 |
| Wang 40 | 2013 | China | Patients with dysplasia | 44 | 54 | Zn sulfate (45) | 14 vitamins & 12 minerals/ daily | 3318 | No | Yes | 6 y | 20 y | Total mortality/ Total cancer mortality/ EC mortality | No effect | 4 |
| 2Qiao41 | 2009 | China | Residents in Linxian | 45 | 52 at start | Zn oxide (22.5) | 5000IU retinol palmitate/ daily | 29584 | Yes | Yes | 5.25 y | 10 y | Total mortality/ Total cancer mortality/ EC mortality | Increased total and stroke mortality | 4 |
| Taylor 42 | 1995 | China | Patients with dysplasia | 44 | 54 | Zn sulfate (45) | 14 vitamins & 12 minerals/ daily | 396 | No | Yes | 30 mo | 0 | Reversion to non-dysplasia | 1.26 (1.06-1.46)/ p=0.005 | 4 |
| 72 mo | 0 | Reversion to non-dysplasia | 1.21 (1.02-1.40) / p=0.02 | ||||||||||||
| Zhang43 | 1995 | China | Residents in Linxian/ Patients with dysplasia | 45/ 44 | 52/ 54 | Zn oxide (22.5) / Zn sulfate (45) | 14 vitamins & 12 minerals/ daily | 400 /375 | Yes | Yes | 5.25 y/6 y | 0 | T cell response | No effect | 4 |
| Taylor 44 | 1994 | China | Rencun commune | 50 | 48 at start | Zn oxide (22.5) | 5000IU retinol palmitate/ daily | 391 | Yes | Yes | 5.25 y | 0 | Prevalence of esophageal cancer | OR=1.02 (0.36-2.91) | 4 |
| Prevalence of esophageal dysplasia or cancer |
OR= 1.12 (0.57-2.20) |
||||||||||||||
| Rao 45 | 1994 | China | Patients with dysplasia | 42 | 57 | Zn sulfate (45) | 14 vitamins & 12 minerals/ daily | 512 | No | Yes | 30 mo | 0 | Overall amount of proliferation | p>0.05 | 4 |
| Lower epithelial level | p>0.05 | ||||||||||||||
| Wahrendorf 46 | 1988 | China | Residents in Huixian | 50 | 35-64 | Zn (50 ) / weekly | 50000IU retinol, 200mg riboflavin/ weekly | 610 | No | Yes | 13.5 mo | 0 | Prevalence of precancerous lesions |
OR=0.78, p=0.05 |
3 |
| Munoz 47 | 1987 | China | Residents in Huixian | 50 | 35-64 | Zn (50 ) / weekly | 50000IU retinol, 200mg riboflavin/ weekly | 170 | No | Yes | 13.5 mo | 0 | Prevalence of micronuclei in esophageal cells |
OR=0.61, p=0.04 |
3 |