Table 2.

Summary of the NHANES data by exposure group. The table shows the total number of subjects with complete observations (n); the number of agents (m); the dimension of the multivariate exposure including the main effect of each agent and each two-way interaction (r); the total number of potential confounders including the main effect of agents in other groups (k); the total number of independent variables including the multivariate exposure, potential confounders, and an intercept (p = r + k + 1); and the p/n ratio.

Exposure group	Sample size (n)	# Agents (m)	Dim(Z) (r)	# Potential confounders (k)	# Indep. variables (p)	p to n ratio (p/n)
Volatile compounds	179	10	55	82	138	0.77
pcbs	558	22	253	59	313	0.56
Phenols	179	3	6	92	99	0.55
Dioxins	201	5	15	83	99	0.49
Furans—dibenzofuran	201	5	15	83	99	0.49
pest.—pyrethyroid	201	1	1	87	89	0.44
Diakyl	225	6	21	76	98	0.44
pest.—phenols	225	4	9	78	88	0.39
pest.—chloroacetanilide	225	1	1	81	83	0.37
pest.—organophosphate	225	1	1	81	83	0.37
Heavy metals	444	13	91	48	140	0.32
Phthalates	387	11	66	51	118	0.30
pest.—organochlorine	288	7	28	53	82	0.28
Nutrients—minerals	158	2	3	37	41	0.26
Polyflourochemicals	444	10	55	51	107	0.24
Hydrocarbons	292	9	45	22	68	0.23
Phytoestrogens	432	6	21	49	71	0.16
Nutrients—vitamin C	444	1	1	60	62	0.14
Nutrients—carotenoid	1370	5	15	33	49	0.04
Nutrients—vitamin A	1370	3	6	35	42	0.03
Nutrients—vitamin B	1370	3	6	35	42	0.03
Nutrients—vitamin E	1370	2	3	36	40	0.03
Cotinine	1370	1	1	37	39	0.03
Nutrients—vitamin D	1370	1	1	37	39	0.03