Cadmium Exposure and Hepato-renal Injury in Response to Cigarette Smoking in Apparently Healthy Active Smokers in Buea-Cameroon

Cigarette smoking in developing countries like Cameroon is increasing with unspecified exposure levels to cadmium, a known toxic chemical. This study conducted in Buea (Southwest Region, Cameroon) aimed to estimate the risk exposure to cadmium inhalation from smoking and its association with the abnormal level of liver and kidney function biomarkers in apparently healthy smokers. A survey recruited smokers to collect data on smoking habits. Cadmium contents in the major cigarette brands selected served to estimate the cadmium Daily Exposure (DE), Weekly Inhalational Exposure (WIE) and the percentage contribution to the Tolerable Weekly Intake (TWI) of cadmium. Serum alanine aminotransferase (ALT) activity, urea, creatinine contents, and urinary albuminuria and glucosuria were measured in blood and urine samples from active and nonsmokers. The 102 smokers enrolled were categorized respectively as light (37.3%; 38/102), moderate (38.2%; 39/102), and heavy (24.5%; 25/102) smokers, smoking an average number of 4.7 {+/-} 0.5, 9.1 {+/-} 1.5, and 19.1 {+/-} 3.0 cigarettes/day, respectively. Cadmium levels in cigarette brands ranged from 0.72-1.08 {micro}g Cd per gram of tobacco removed from the cigarette. Heavy smokers exceeded the permitted cadmium No Significant Risk Level (NSRL) by up to 28-fold, contributing 4-8% to the cadmium TWI. Serum ALT activity and creatinine content were significantly higher (P<0.05) in smokers groups compared to non-smokers. Also, moderate and heavy smokers were at a significantly higher risk (relative risk 6.90-13.32; P<0.05) of displaying abnormal elevated serum urea content, positive albuminuria and glucosuria. Our findings demonstrated that healthy active smokers are highly exposed to cadmium inhalation and are at higher risk of displaying abnormally increased levels of biochemical markers of liver and kidney functions, indicating risks of organ damage.