Table 3. Comparison of geometric mean values of metals in urine samples from various populations in GCC countries: Current study vs. previously reported studies.

Element	Country	N	Population characteristics	Year of sampling	Population group (age)	Mean	Source
Cadmium (Cd)	UAE	144	Healthy female adults	2023	16–24	0.24 μg/g cr	Current study
	Qatar	239	farm workers who are currently working and residing in farms in Qatar	2012–2013	<20->50	1.09 μg/L	[41]
	Saudi Arabia	995	Healthy Saudi non-smokers and non-occupationally exposed women in Al-Riyadh city	2011–2013	17–48	0.96 μg/g cr	[40]
	Saudi Arabia	400	Healthy Volunteers	NA	20->70	0.54 μg/L	[39]
	Saudi Arabia	400	Deceased subjects	NA	20->70	1.56 μg/L	[39]
Cobalt (Co)	UAE	144	Healthy female adults	2023	16–24	1.01 μg/g cr	Current study
	Qatar	239	farm workers who are currently working and residing in farms in Qatar	2012–2013	<20->50	0.47 μg/L	[41]
Manganese (Mn)	UAE	144	Healthy female adults	2023	16–24	0.30 μg/g cr	Current study
	Qatar	239	farm workers who are currently working and residing in farms in Qatar	2012–2013	<20->50	2.15 μg/L	[41]
	Saudi Arabia	206	Healthy Saudi lactating mothers	2011–2013	19–45	3.06 μg/L	[42]
	Saudi Arabia	206	Healthy Saudi infants	2011–2013	2.9–12.39 months	3.68 μg/L	[42]
Copper (Cu)	UAE	144	Healthy female adults	2023	16–24	6.94 μg/g cr	Current study
	Qatar	239	farm workers who are currently working and residing in farms in Qatar	2012–2013	<20->50	15.0 μg/L	[41]
Silver (Ag)	UAE	144	Healthy female adults	2023	16–24	1.63 μg/g cr	Current study
	Saudi Arabia	400	Healthy Volunteers	NA	20->70	0.91 μg/L	[39]
	Saudi Arabia	400	Deceased subjects	NA	20->70	2.78 μg/L	[39]
Barium (Ba)	UAE	144	Healthy female adults	2023	16–24	0.77 μg/g cr	Current study
	Qatar	239	farm workers who are currently working and residing in farms in Qatar	2012–2013	<20->50	22.5 μg/L	[41]
Chromium (Cr)	UAE	144	Healthy female adults	2023	16–24	0.40 μg/g cr	Current study
	Qatar	239	farm workers who are currently working and residing in farms in Qatar	2012–2013	<20->50	0.55 μg/L	[41]
Iron (Fe)	UAE	144	Healthy female adults	2023	16–24	9.36 μg/g cr	Current study
	Qatar	239	farm workers who are currently working and residing in farms in Qatar	2012–2013	<20->50	34.1 μg/L	[41]
Nickel (Ni)	UAE	144	Healthy female adults	2023	16–24	1.70 μg/g cr	Current study
	Qatar	239	farm workers who are currently working and residing in farms in Qatar	2012–2013	<20->50	2.95 μg/L	[41]
Lead (Pb)	UAE	144	Healthy female adults	2023	16–24	14.03 μg/g cr	Current study
	Qatar	239	farm workers who are currently working and residing in farms in Qatar	2012–2013	<20->50	2.50 μg/L	[41]
	Saudi Arabia	206	Healthy Saudi lactating mothers	2011–2013	19–45	6.794 μg/L	[42]
	Saudi Arabia	206	Healthy Saudi infants	2011–2013	2.9–12.39 months	6.054 μg/L	[42]
	Saudi Arabia	995	Healthy Saudi non-smokers and non-occupationally exposed women in Al-Riyadh city	2011–2013	17–48	10.8 μg/g cr	[40]
	Saudi Arabia	400	Healthy Volunteers	NA	20->70	1.31 μg/L	[39]
	Saudi Arabia	400	Deceased subjects	NA	20->70	17.80 μg/L	[39]
Arsenic (As)	UAE	144	Healthy female adults	2023	16–24	13.02 μg/g cr	Current study
	Qatar	239	farm workers who are currently working and residing in farms in Qatar	2012–2013	<20->50	47.8 μg/L	[41]
	Saudi Arabia	400	Healthy Volunteers	NA	20->70	18.32 μg/L	[39]
	Saudi Arabia	400	Deceased subjects	NA	20->70	3.00 μg/L	[39]