Smoking years predicts low BMD in Japanese men
MedWire News: Number of years of smoking is the strongest smoking-related factor influencing bone mineral density (BMD) in elderly men, Japanese researchers have found.
Noting that smoking is related to reduced BMD and risk for osteoporosis, the team further examined the impact of smoking and smoking cessation in 1576 Japanese men aged 65 years or older.
Lumbar spine BMD showed a significant and decreasing trend across never, former, and current smokers at 1.045, 1.030, and 1.001 g/cm2, respectively. The relationship between lumbar spine BMD and smoking remained significant even after adjusting for age, height, weight, physical activity, and milk and alcohol consumption.
A marginal but significant trend was also identified for total hip BMD across the never, former, and current smoking groups.
While the mechanism of smoking on BMD is unknown, the researchers hypothesize that lumbar spine BMD may be more affected by smoking because peak bone mass is achieved later in life than total hip bone mass, which peaks at adolescence.
“This suggests that total hip bone mass could be achieved before smoking initiation,” postulate M Iki (Kinki University School of Medicine, Osaka) and co-workers.
Further analysis of never smokers and current or former smokers showed that both lumbar spine and total hip BMD fell with the number of pack-years and smoking-years, after adjusting for age, height, weight, and daily cigarettes smoked.
When examining only former or current smokers, BMD at both sites fell with number of smoking-years after adjusting for age, height, weight, and daily cigarettes smoked.
Of note, smoking had no impact on levels of the bone turnover markers serum osteocalcin or tartrate resistant acid phosphatase isoenzyme 5b.
“Further studies about the effects of smoking on bone formation and resorption should be conducted,” recommend the researchers in the journal Osteoporosis International.
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By Lynda Williams