Naïve and multivariate mixed-effect regression models for weekly pesticide exposure in Zarcero County, Costa Rica, 2016
| Model A EXPOSUREWEEK All farmers (n=442; co=280, su=124, or=38)* | Variance component | % | GSD | R0.95† | ICC | Model B EXPOSURE WEEK‡ >0 (n=312; co=202, su=89, or=21)* | Variance component | % | GSD | R0.95† | ICC |
| Empty model | Empty model | ||||||||||
| Random effect intercept | 1.16 | 0.39 | 2.93 | 67.79 | 0.39 | Random effect intercept | 0.74 | 0.53 | 2.36 | 29.13 | 0.53 |
| Random error | 1.79 | 0.61 | 3.81 | 188.73 | Random error | 0.66 | 0.47 | 2.25 | 24.18 | ||
| Multivariate model | Multivariate model | ||||||||||
| Random effect intercept | 1.03 | 0.37 | 2.76 | 53.74 | 0.37 | Random effect intercept | 0.48 | 0.56 | 2.00 | 15.12 | 0.56 |
| Random error | 1.75 | 0.63 | 3.75 | 178.16 | Random error | 0.38 | 0.44 | 1.85 | 11.13 | ||
| Full model explains | 6% of variability | Full model explains | 39% of variability | ||||||||
| Predictor | exp(ß) | exp(ß) (95% CI) | P value | Predictor | exp(ß) | exp(ß) (95% CI) | P value | ||||
| Intercept | 6.40 | 3.41 | 16.05 | <0.01 | Intercept | 27.25 | 16.24 | 49.12 | <0.01 | ||
| Farm type | Organic | 1.00 | 1.00 | 1.00 | Farm type | Organic | 1.00 | 1.00 | 1.00 | ||
| Sustainable | 1.61 | 0.77 | 3.32 | 0.23 | Sustainable | 1.00 | 0.60 | 1.68 | 0.99 | ||
| Conventional | 2.15 | 1.09 | 4.23 | 0.03 | Conventional | 1.36 | 0.84 | 2.20 | 0.21 | ||
| Years worked with pesticides | 0.99 | 0.98 | 1.01 | 0.29 | Years worked with pesticides | 0.99 | 0.98 | 1.00 | 0.26 | ||
| Training | No | 1.00 | 1.00 | 1.00 | Training | No | 1.00 | 1.00 | 1.00 | ||
| Yes | 0.67 | 0.45 | 0.99 | 0.04 | Yes | 0.62 | 0.48 | 0.81 | <0.01 | ||
| Nationality | Costa Rica | 1.00 | 1.00 | 1.00 | Nationality | Costa Rica | 1.00 | 1.00 | 1.00 | ||
| Nicaragua | 1.14 | 0.74 | 1.77 | 0.55 | Nicaragua | 1.12 | 0.84 | 1.50 | 0.43 | ||
Model A: all study participants who applied pesticides during the last 12 months before the baseline visit (221 farm workers, 442 observations).
Model B: study participants who applied pesticides during the week before the baseline and/or follow-up visits (190 farm workers, 312 observations.
*co, conventional; or, organic; su, sustainable.
†ln transformed values.
‡130 observations were 0 as participants did not apply pesticides in the week before the baseline or follow-up visit.
GSD, geometric SD;ICC, intraclass correlation coefficient; R0.95, ratio of the 97.5th and 2.5th percentile of the intraindividual and interindividual exposure distribution.