Smoking increases bone loss and decreases intestinal calcium absorption

Area of Science:

• Gerontology
• Bone Metabolism
• Nutritional Science

Background:

• Cigarette smoking is a known risk factor for bone mineral density (BMD) loss.
• The precise mechanisms linking smoking to accelerated bone loss and impaired calcium absorption remain incompletely understood.

Purpose of the Study:

• To investigate the relationship between smoking and the rate of BMD change at the femoral neck, spine, and total body.
• To examine the impact of smoking on intestinal calcium absorption in elderly individuals.

Main Methods:

• A 3-year placebo-controlled study involving 402 elderly participants (32 smokers, 370 nonsmokers) receiving calcium and vitamin D supplementation.
• Bone mineral density (BMD) changes were assessed annually.
• Intestinal calcium absorption was measured using a single isotope method (45Ca) at multiple time points in a subset of participants.

Main Results:

• Smokers exhibited significantly higher rates of BMD loss at the femoral neck and total body compared to nonsmokers.
• Intestinal calcium absorption fraction was significantly lower in smokers than in nonsmokers, with heaviest smokers showing the lowest absorption.
• Smokers demonstrated a lower proportionate increase in urinary calcium/creatinine excretion following supplementation.

Conclusions:

• Smoking accelerates bone loss in the elderly, specifically affecting the femoral neck and total body BMD.
• Reduced intestinal calcium absorption is identified as a potential contributing factor to smoking-related bone loss.
• These findings highlight the detrimental effects of smoking on skeletal health in older adults.