Secondhand smoke increases osteoporosis risk in postmenopausal women
MedWire News: Postmenopausal Korean women who have never smoked but who are exposed to secondhand smoke (SHS) are at increased risk for developing osteoporosis compared with unexposed women, indicate study results.
Furthermore, being exposed to high levels of SHS in the home was associated with a significantly increased risk for both lumbar and femoral neck osteoporosis compared with women who did not live with a smoker, say the researchers.
The finding implies that "SHS alters bone metabolism," they write in Osteoporosis International.
The study involved 925 women aged at least 55 years who had not smoked more than 100 cigarettes in their lifetime and had urinary cotinine levels (a biomarker of nicotine exposure) below 100 ng/mL or higher. In all, 212 (22.9%) self-reported exposure to SHS.
K Lee (Seoul National University College of Medicine, South Korea) and colleagues defined SHS as "the smoke emitted from the burning end of a cigarette or from other tobacco products usually in combination with the smoke exhaled by the smoker."
Exposure to SHS at work and at home was significantly associated with urinary cotinine concentration, with a stronger association noted for exposure at home. Specifically, women with family members who smoked had a higher mean cotinine concentration than the 713 women in the study who were not exposed to SHS (controls), at 12.28 ng/mL versus 7.31 ng/mL.
Neither total SHS exposure per day nor exposure during working hours were significantly associated with osteoporosis in a multivariate analysis, remark Lee et al.
However, the duration of SHS exposure at home was positively and significantly associated with femoral neck osteoporosis, with any home exposure resulting in an adjusted odds ratio of 2.26 compared with none.
Indeed, living with a family member who smoked increased the risk for osteoporosis of the femoral neck by 3.68 times. Also, if cohabiting smokers smoked more than 20 cigarettes per day, the risk for both lumbar and femoral neck osteoporosis in the SHS-exposed women increased by 5.40 and 4.35 times, respectively, compared with having no cohabiting smokers.
"We believe that interventions tailored to individuals in SHS environments are needed," conclude Lee and co-investigators.
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By Sarah Guy