Ten cross sectional/case-control and four follow-up studies (total number of participants not stated, but n >3932 for cross-sectional/case control studies and n=1044 for follow-up studies).
Qualitative summary of cross sectional/case control studies.
Children who used fluoride supplements during the first several years of life had a significant increase in the risk of developing dental fluorosis. The OR of developing fluorosis in users of fluoride supplements during the first eight years of life ranged from 1.3 to 10.7.
Qualitative summary of follow-up studies.
All studies reported an increased risk of fluorosis although the confidence intervals in many studies were wide.
Meta-analysis of cross sectional/case control studies.
The odds ratio of dental fluorosis in users compared with non-users (all studies) ranged between 2.1 (95% CI: 1.7, 2.5) and 2.3 (95% CI: 1.5, 3.4). The odds ratio of dental fluorosis in users who took fluoride supplements during the first six years of life compared with non-users ranged between 2.4 (95% CI: 1.9, 3.1) and 2.6 (95% CI: 1.7, 4.1).
Meta-analysis of follow-up studies.
The relative risk of dental fluorosis in users compared with non-users (all studies) ranged between 1.3 (95% CI: 2.6, 5.3) and 6.6 (95% CI: 2.9, 15.2). The relative risk for the follow-up studies in users who took fluoride supplements during the first six years of life compared with non-users was between 5.5 (95% CI: 2.7,11.4) and 12.2 (95% CI: 4.9, 30.4).