Table 3.

Variation in rate of loss to follow-up between baseline and 2-year examinations

	Number (%) of children lost to follow-up	P-value*
All children	123/666 (18%)
Community factors
Study group
Control communities	60/322 (19%)	0.92
Intervention communities	63/281 (18%)
Population size
≤450 people	51/259 (20%)	0.54
>450 people	72/407 (18%)
Distance to nearest hospital
<250 km	16/74 (22%)	0.43
≥250 km	107/592 (18%)
Fluoride concentration in drinking water
<0.6 ppm F	105/577 (18%)	0.66
≥0.6 ppm F	18/89 (20%)
Child factors
Age
18–<30 months	51/241 (21%)	0.23
30–<40 months	43/229 (19%)
40–<48 months	29/196 (15%)
Sex
Male	57/326 (17%)	0.55
Female	66/340 (19%)
Baseline d3mfs
0 surfaces	50/238 (21%)	0.40
1–5 surfaces	40/223 (18%)
≥6 surfaces	33/205 (16%)

^*P-values test null hypothesis of equivalence in % followed up between rows using Chi-square test (age group, baseline d₃mfs) or Fisher's exact test (all other comparisons)