Table 2.

Fecundability hazard ratios (FHR) and 95% confidence intervals (CI) for time to pregnancy (TTP) associated with drinking water arsenic exposure (n = 94).

Predictor ^a	FHR	95% CI	P-value
Average arsenic level (μg/L)	1.08	1.02, 1.13	0.01
Maternal age (years)	1.34	1.25, 1.44	< 0.0001
High school diploma/some ^b college/technical school	1.17	0.56, 2.46	0.68
University diploma ^b	1.28	0.65, 2.51	0.47
Smoked > 100 lifetime cigarettes ^c	0.93	0.56, 1.55	0.78
Maternal age (years) x log TTP (cycles)	0.80	0.77, 0.84	< 0.0001
Average arsenic level (μg/L) x log TTP (cycles)	0.93	0.89, 0.98	0.01
Peak arsenic level (μg/L)	1.06	1.01, 1.11	0.02
Maternal age (years)	1.34	1.25, 1.44	< 0.0001
High school diploma/some college/technical school ^b	1.14	0.54, 2.41	0.74
University diploma ^b	1.35	0.68, 2.65	0.39
Smoked > 100 lifetime cigarettes ^c	0.97	0.58, 1.61	0.90
Maternal age (years) x log TTP (cycles)	0.81	0.77, 0.84	< 0.0001
Peak arsenic level (μg/L) x log TTP (cycles)	0.95	0.91, 0.99	0.02
Daily arsenic dose (μg)	1.06	1.01, 1.11	0.01
Maternal age (years)	1.34	1.24, 1.44	< 0.0001
High school diploma/some college/technical school ^b	1.12	0.53, 2.38	0.77
University diploma ^b	1.33	0.67, 2.63	0.42
Smoked > 100 lifetime cigarettes ^c	0.98	0.59, 1.63	0.95
Maternal age (years) x log TTP (cycles)	0.81	0.77, 0.84	< 0.0001
Daily arsenic dose (μg) x log TTP (cycles)	0.95	0.91, 0.99	0.02

NOTE: Bold typeface indicates P < 0.05. FHR > 1.0 indicates a higher conditional likelihood for pregnancy and FHR < 1.0 indicates a lower conditional likelihood for pregnancy.

Effect estimates adjusted for all other variables in the table;

‘No high school diploma’ is reference category;

‘Smoked < 100 lifetime cigarettes’ is reference category.