Institution: University of Ibadan

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Abstract

Despite growing recognition that cancer is associated with multiple risk factors interacting, the combined effects of HIV infection and occupational toxic metals exposure as cancer risk factors have received little attention. Therefore, this study investigated the effects of these factors on selected toxic metal and trace element in relation to carcinogenicity. A comparative cross-sectional study of 248 adults (aged 18-65 years) was conducted, with participants divided into four groups based on HIV status and occupational exposure to toxic metals: HIV-positive exposed [(HPE), (n=62)], HIV-positive unexposed [(HPU), (n=66)], HIV-negative exposed [(HNE), (n=60)], and HIV-negative unexposed [(HNU), (n=60)]. The HIV-positive and HIV-negative groups had similar occupations, ages, and other characteristics. Blood cadmium (Cd), lead (Pb), mercury (Hg) and selenium (Se) were measured by inductively coupled plasma optical emission spectrometry, while serum zinc (Zn) and copper (Cu) were determined using atomic absorption spectrometry. Lead, cadmium, and mercury were significantly elevated in HPE (14.92±0.54 µg/dl, 0.25±0.01 µg/L, 1.93±0.08 µg/L respectively) compared with the HNU (11.07±0.48 µg/dl, 0.17±0.01 µg/L, 0.76±0.05 µg/L), p<0.01, respectively. Zinc, a p53 activator and cell cycle regulator, was significantly lower in the HPE than in HPU, HNE, and HNU (p=0.02, p<0.01, p<0.01 respectively). Toxic metal exposure and HIV-positive status both increased Pb and Hg levels while decreasing Zn, and the effects were additive. Occupationally exposed HIV-positive individuals had a higher toxic metal burden and lower zinc levels, both of which are important determinants of genome instability and may exacerbate DNA damage and increase cancer risk.
Keywords: Human immunodeficiency virus, Occupational exposure, Toxic metal, Cancer risk.

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