Table 2.

Results of Poisson regression analysis of the association between contemporaneous and earlier rates of genital chlamydial infection with rates of ectopic pregnancy by age group among women in Uppsala, Sweden, 1985-95. Rate ratios (95% confidence intervals) estimate the effect of an increase of five positive test results per 100 tests on the rate of chlamydial infection

Rate of chlamydial infection	Age group
	20-24	25-29	30-34	35-39
In same year	1.85 (1.44 to 2.38)	1.64 (1.24 to 2.17)	1.11 (0.73 to 1.67)	0.82 (0.51 to 1.32)
1 year earlier	1.67 (1.29 to 2.15)	1.72 (1.33 to 2.22)	2.27 (1.53 to 3.37)	1.24 (0.76 to 2.04)
2 years earlier	1.46 (1.13 to 1.89)	1.56 (1.22 to 2.00)	1.82 (1.25 to 2.66)	2.58 (1.45 to 4.60)
3 years earlier	1.34 (1.02 to 1.76)	1.64 (1.27 to 2.12)	1.41 (0.96 to 2.06)	1.55 (0.89 to 2.70)
4 years earlier	1.21 (0.91 to 1.62)	1.71 (1.30 to 2.23)	1.83 (1.21 to 2.76)	1.19 (0.68 to 2.08)
5 years earlier	1.33 (0.97 to 1.82)	1.49 (1.09 to 2.03)	1.70 (1.10 to 2.61)	1.31 (0.66 to 2.58)