Which of the following is a possible indicator of lead poisoning in adults?

Abdominal pain serves as a potential indicator of lead poisoning in adults due to the physiological effects lead can have on the gastrointestinal system. Lead interferes with various enzymatic processes in the body, which can lead to symptoms such as colicky abdominal pain, constipation, and other gastrointestinal disturbances. In cases of lead toxicity, the body struggles to manage the metal, leading to irritation and dysfunction within the digestive tract.

Other options listed, while they may be symptoms of various health issues, are not as directly linked to lead poisoning in adults. Joint pain could arise from many different causes, including arthritis or other muscular issues, rather than being a specific hallmark of lead exposure. Vision problems may relate to other neurological or eye conditions and are not commonly recognized as direct indicators of lead toxicity. Nausea can be caused by a wide range of illnesses and conditions. While it may occasionally be experienced by individuals with lead poisoning, abdominal pain is more specifically associated with the gastrointestinal impact of lead toxicity and is thus a more definitive indicator.