Cadmium levels linked to low BMD
MedWire News: Exposure to cadmium may increase the risk for osteopenia and osteoporosis, US researchers have found.
The team used data from the Third National Health and Nutrition Examination Survey to show that increasing levels of urinary cadmium are associated with an increased risk for pathologically low bone mineral density (BMD).
Qing Wu (Mayo Clinic, Scottsdale, Arizona), and colleagues note the correlation remained after adjusting for confounding factors such as age, body mass index (BMI), and calcium intake, and within subgroups of gender, race, and smoking status.
However, they note: "A prospective study would be required to establish a causal relationship between cadmium and osteoporosis."
The team examined urinary cadmium levels and rates of World Health Organization defined osteopenia (T-score >-2.5 but <-1) and osteoporosis (T-score <-2.5) in 10,979 men and women aged 30-90 years.
The odds ratio (OR) for osteopenia and osteoporosis increased in a dose-dependent manner with urinary cadmium levels after adjusting for age, gender, ethnicity, BMI, calcium intake, and physical inactivity, the team reports in the journal Osteoporosis International. For each 1.00-1.99 µg of urinary cadmium per g of urinary creatinine, the ORs for osteopenia and osteoporosis were 1.49 and 1.78, respectively. For each 2.00 or greater µg/g increase the corresponding ORs were 2.05 and 3.80.
Moreover, the relationship was consistent in men and women, participants aged above and below 50 years, smokers and nonsmokers, and in White, non-Hispanic Black, and Hispanic participants.
Wu et al note that the underlying cause of cadmium-induced low BMD is unclear. They suggest that the toxic metal may disrupt calcium metabolism through damage to the renal or gastrointestinal systems, or alter bone resorption.
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
By Lynda Williams