Multivariable adjusted association between Q fever incidence in 2008–2010 and three adverse pregnancy outcomes
| Variable | Category | Preterm delivery, OR (95% CI) | Child small for gestational age, OR (95% CI) | Perinatal mortality, OR (95% CI) |
|---|---|---|---|---|
| Interaction term: incidence Q fever postal-code area×period† | <4.59 notifications/10 000 inhabitants, in 2008–2010 | 1.01 (0.91 to 1.11) | 1.04 (0.96 to 1.13) | 0.86 (0.65 to 1.14) |
| 4.59–10.61 notifications/10 000 inhabitants, in 2008–2010 | 1.04 (0.92 to 1.16) | 1.13 (1.03 to 1.24) | 0.84 (0.62 to 1.14) | |
| 10.62–21.50 notifications/10 000 inhabitants, in 2008–2010 | 0.87 (0.76 to 1.00) | 1.03 (0.92 to 1.15) | 0.80 (0.54 to 1.19) | |
| ≥21.51 notifications/10 000 inhabitants, in 2008–2010 | 1.13 (0.98 to 1.31) | 1.04 (0.92 to 1.16) | 1.04 (0.70 to 1.57) | |
| Reference group* | Reference | Reference | Reference |
Number of observations used: 312 420.
*Reference group included pregnancy outcomes in areas not affected by Q fever in 2008–2010 combined with outcomes in areas affected and unaffected by Q fever in the preoutbreak years of 2003–2004.
†Adjusted for confounders age of the mother, ethnic background, smoking, socioeconomic status, urbanisation degree, cattle density, goat density and sheep density.