Table 2. . Relationships between cadmium or lead exposure and obesity and its correlates .

Author (year)	PMID	Study location	Sample size/characteristics	Exposure	Measured outcomes	Results	Ref.
Ba (2016)	27634282		In vivo (mice)	Early life cadmium exposure	Adiposity (body fat, lean mass and total mass), plasma TC, LDL, VLDL, HDL, plasma and liver TG, plasma free fatty acids, plasma leptin, gut microbiota and hepatic gene expression	In male mice, LDC exposure led to fat accumulation and increased levels of plasma TC, TG and free fatty acids and liver TG, alterations in gut microbiota and hepatic gene expression related to fatty-acid and lipid metabolism was enhanced. Transplant of fecal microbiota from LDC exposed male mice into unexposed male controls led to increased mass and percent body fat in these recipients	[72]
Wu (2016)	26962054		In vivo (mice)	Early-life lead exposure	Gut microbiota composition and body weight	Increased adult body weight in male mice. Decrease of aerobes and increase of anaerobes in lead exposed mice. Changes in gut microbiota and body weight in male mice	[70]
Cassidy-Bushrow (2016)	26358768	USA	n = 299 children (ages 2–3 years)	Early-life lead exposure	BMI	Having detectable blood lead levels associated with smaller body size at 2–3 years of age	[61]
Faulk (2014)	25105421	——	In vivo (mice)	Early-life lead exposure	Energy expenditure, spontaneous activity, food intake, body weight and composition and glucose tolerance	Increases in food intake at differing ages for females and males. Increased body fat, body weight and insulin response in males	[68]
Delvaux (2014)	24742724	Belgium	n = 114 children ages 7–9 years (n = 57 females and 57 males)	Prenatal cadmium exposure	BMI, abdominal fat (waist circumference) and subcutaenous fat (skinfolds)	Inverse association between prenatal cadmium exposure and body weight, BMI, abdominal fat and subcutaenous fat in females	[62]
Scinicariello (2013)	24099784	USA	NHANES data 1999–2006 children and adolescents ages 3–19 years	Lead exposure	BMI	Inverse association between blood lead levels and BMI	[63]
Tian (2009)	19404590	China	n = 106 infants measured again at ∼4.5 years	Prenatal cadmium exposure	Birth weight and height, weight and height at ∼4.5 years, WPPSI-R	Higher levels of cord blood cadmium associated with lower birth weight and length and at ∼4.5 years, lower height and WPPSI-R-IQ full scores	[11]
Leasure (2008)	18335103	——	In vivo (mice)	Early-life lead exposure	Body weight, motor activity, dopamine levels	Late onset obesity in 1-year-old male mice and motor abnormalities in male mice	[69]
Berkowitz (2006)	16376613	USA	n = 169,878 birth certificate data for five communities in proximity to the Bunker Hill Superfund site	Prenatal lead exposure (due to lead smelter fire). Air emissions of high concentrations of lead	Preterm birth, SGA, TLBW and TMBW among term infants	Maternal lead exposure associated with increased risk of TLBW and SGA and reduced TMBW	[9]
Sanin (2001)	11331680	Mexico	n = 329 mother–infant pairs	Early-life lead exposure	Weight at age one month and weight gain from birth to one month	Maternal lead burden inversely associated with infant weight at one month of age and weight gain between birth and one month of age	[60]
Gonzalez-Cossio (1997)	9346987	Mexico	n = 272 mother–infant pairs	Early-life lead exposure	Birth weight	Maternal bone-lead burden inversely associated with birth weight	[10]
Kim (1995)	8529592	USA	n = 236 at age ∼7 years (1975–1978) and follow-up 13 years later n = 58 at age ∼20 years (1989–1990)	Lead exposure	Weight and height	Dentin lead levels were positively associated with BMI in 1975–1978 and increase in BMI between 1975–1978 and 1989–1990	[64]

HDL: High-density lipoprotein; LDC; Low dose cadmium; LDL: Low-density lipoprotein; SGA: Small for gestational age; TC: Total cholesterol; TG: Triglycerides; TLBW: Term low birth weight; TMBW: Term mean birth weight; VLDL: Very low-density lipoprotein.