Factors associated with blood mercury concentrations and their interactions with three glutathione S-transferase genes (GSTT1, GSTM1, and GSTP1): an exposure assessment study of typically developing Jamaican children

Table 1 Sociodemographic characteristics of Jamaican TD children and their parents and children’s GST genotypes (n = 375)

Variables		Categories	n (%)
Child	Sex	Male	307 (81.9)
	Sex	Female	68 (18.1)
	Age at enrollment (months)	Age < 72	281 (74.9)
	Age at enrollment (months)	Age ≥ 72	94 (25.1)
	Race	Afro-Caribbean	365 (97.3)
	Parish of birth	Kingston parish	232 (61.9)
	Parish of birth	Other parishes ^a	143 (38.1)
	*GSTT1* ^b	DD ^c	92 (25.8)
	*GSTT1* ^b	I* ^d	264 (74.2)
	*GSTM1* ^e	DD	89 (24.9)
	*GSTM1* ^e	I*	268 (75.1)
	*GSTP1* ^f	Ile/Ile	96 (26.7)
		Ile/Val	182 (50.7)
		Val/Val	81 (22.6)
Maternal age at child’s birth (years) ^g		Age < 35	326 (88.4)
Maternal age at child’s birth (years) ^g		Age ≥ 35	43 (11.7)
Parental education level at child’s birth ^h		Both up to high school ⁱ	199 (55.9)
Parental education level at child’s birth ^h		At least one beyond high school ^j	157 (44.1)
Socioeconomic status (SES) of parents/family		High SES (own a car)	151 (40.3)

^a Includes Portland, Trelawny, Westmoreland, Clarendon, St. Andrew, St. Mary, St. James, St. Elizabeth, St. Catherine, St. Thomas, St. Ann, Hanover, or Manchester parishes of Jamaica. ^b GSTT1 was missing for 19 children. ^c DD specifies the null alleles for GSTT1 and GSTM1 genes. ^d I* (I/I or I/D) specifies the homozygote (I/I) or a heterozygote (I/D) for GSTT1 and GSTM1 genes. ^e GSTM1 was missing for 18 children. ^f GSTP1 was missing for 16 children. ^g Maternal age was missing for 6 mothers. ^h Parental education level was missing for 19 participants. ⁱ Up to high school education means attending primary/junior secondary and secondary/high/technical schools. ^j Beyond high school education means attending a vocational, tertiary college, or university

ISSN: 1471-2431