Table 2.

Sensitivity analyses: associations between blood heavy metal levels and constipation.

Exposure	Primary analysis (model 3) OR (95% CI)	P	Sensitivity 1: Excluding eGFR OR (95% CI)	P	Sensitivity 2: Excluding extreme values OR (95% CI)	P
Continuous variables (log-transformed)
Lead	0.496 (0.331–0.745)	.004	0.502 (0.336–0.750)	.003	0.459 (0.248–0.850)	.02
Cadmium	1.009 (0.759–1.343)	.94	1.013 (0.768–1.335)	.92	1.091 (0.653–1.824)	.71
Mercury	0.701 (0.542–0.905)	.01	0.700 (0.544–0.900)	.01	0.752 (0.583–0.969)	.03
Categorical variables (quartiles)
Lead Q1	Reference	–	Reference	–	–	–
Lead Q2	0.759 (0.546–1.057)	.08	0.761 (0.571–1.015)	.06	–	–
Lead Q3	0.642 (0.419–0.985)	.05	0.646 (0.443–0.941)	.03	–	–
Lead Q4	0.690 (0.417–1.143)	.10	0.695 (0.449–1.077)	.08	–	–
Cadmium Q1	Reference	–	Reference	–	–	–
Cadmium Q2	0.763 (0.544–1.071)	.09	0.765 (0.571–1.024)	.06	–	–
Cadmium Q3	0.822 (0.554–1.221)	.21	0.824 (0.584–1.163)	.19	–	–
Cadmium Q4	0.908 (0.539–1.528)	.60	0.910 (0.581–1.425)	.59	–	–
Mercury Q1	Reference	–	Reference	–	–	–
Mercury Q2	0.802 (0.579–1.109)	.12	0.801 (0.604–1.064)	.10	–	–
Mercury Q3	0.835 (0.552–1.262)	.26	0.834 (0.582–1.195)	.23	–	–
Mercury Q4	0.673 (0.463–0.980)	.04	0.673 (0.485–0.933)	.03	–	–

The primary analysis was fully adjusted as in model 3.

Sensitivity analysis 1 excluded adjustment for eGFR.

Sensitivity analysis 2 excluded extreme metal values (below the first percentile or above the 99th percentile) and was performed only for continuous exposure models.

ORs and 95% CIs were estimated using survey-weighted logistic regression models.

CI = confidence interval, eGFR = estimated glomerular filtration rate, OR = odds ratio.