June 16, 2022, 2:42 p.m. News Staff — Cigarette smoking is the leading cause of preventable disease, disability and death in the United States. Although the Academy and other organizations have shown great success in raising awareness about the dangers associated with smoking, nearly 31 million adults in the United States still smoke cigarettes. Evidence from the CDC and other groups indicates that adult men are more likely than adult women to smoke; as such, adult men are more likely than adult women to be at increased risk of smoking-related conditions, including several conditions that affect bone health.
While numerous studies have examined the effects of cigarette smoking on fracture risk in men, many of them have concentrated on specific areas of the body such as the spine and the hip. Results of a new meta-analysis of cohort studies published in the Nature open-access journal Scientific Reports illustrate the effect cigarette smoking has on fracture risk not just in those areas but throughout the body. The meta-analysis found that overall, cigarette smoking was associated with a significant increase in fracture risk in men, which could also lead to increased risks of major disability and early death.
“Osteoporosis and fractures are typically something we discuss more with our female patients as they age unless a male patient has a specific disease state or medication that elevates the risk for fracture,” said Lynn Fisher, M.D., a member of the Academy’s Commission on Health of the Public and Science, in an email to AAFP News. “Since tobacco use is still prevalent despite the risks, family physicians will frequently encounter male patients who would benefit from smoking cessation counseling, and now we can share this knowledge in addition to other well-known risks.”
For the meta-analysis, two investigators conducted literature searches on the Medline, Embase, PsycInfo, Scopus, ISI Web of Science and Open Grey databases, as well as Google Scholar and WorldCat Dissertations. The last literature search was conducted Apr. 28, 2021.
To be eligible for the meta-analysis, articles had to use prospective or retrospective cohort study designs; report individual smoking status; include risk estimates for any fracture, or provide sufficient information to estimate fracture risk; and report results for men. In addition, the researchers include only studies that reported relative risk or hazard ratio of fractures associated with smoking, or that had the data necessary for determining risk ratio.
To calculate pooled risk ratio, the authors used two models: a frequentist approach, which calculated risk ratio based on the available data, and a Bayesian approach, which also estimated the probability that smoking increased risk fractures by certain percentages.
After removing duplicate references and articles that did not meet the investigators’ selection criteria, the meta-analysis included 27 studies. Altogether the researchers analyzed more than 29,000 cases of fractures in adult men, including fractures of the femur, forearm, hip, humerus, lower leg, shoulder, shoulder, spine and wrist.
Compared with non-smokers, men who smoked cigarettes had between a 36% and 37% overall increased risk of any type of fracture, based on the Bayesian and frequentist approaches, respectively. Using the Bayesian method, the researchers also estimated a 99% probability that smoking increased fracture risk by more than 0%, and a 98% probability that smoking increased fracture risk by 20%.
In addition, the meta-analysis showed risk increases based on patient age and the type of fracture reported. Male smokers 60 and older had a 48% increased fracture risk compared with nonsmokers, while the risks of hip and vertebral fractures were increased by 46% and 48%, respectively.
“The association between smoking and fracture risk was consistent in all sensitivity analyses with different inclusion criteria, various subgroup analyses and analysis after excluding two outlier/influential studies, which suggests consistency and robustness of findings in this meta-analysis,” the authors wrote.
In a discussion on the paper’s findings, the investigators offered several theories as to how smoking affects fracture risk. They cited longstanding research suggesting that chemicals in cigarette smoke negatively affect bone cells, which could affect the body’s ability to absorb calcium and vitamin D and result in low bone-mineral density. They also pointed to previous research indicating that smoking can interfere with tissue repair, which could leave the body more susceptible to wounds and impede fracture healing.
The authors noted a number of limits to their research, including the use of self-reported data in some trials, the possibility of publication bias and the fact that the findings could be over- or underestimated based on various confounders in the different studies. Despite these limits, the authors thought that their findings were reliable and robust, and that the study limitations were unlikely to alter the overall results.
“In summary, our comprehensive meta-analysis found a significant association between smoking and increased risk of fractures,” the authors concluded. “Our findings were consistent in both frequentist and Bayesian approaches, as well as all subgroup analyses, sensitivity analysis and the analysis with publication bias correction. More importantly, our results have crucial implications in public health, with the most apparent being that quitting smoking can reduce an individual’s risk of bone fracture, but now and later in life.”
Fisher, who also serves as an assistant professor in the Department of Family and Community Medicine at the University of Kansas School of Medicine-Wichita, considered the findings from the meta-analysis as another set of facts that FPs can use to speak with male patients about the harms of smoking and motivate those who do smoke to quit.
“Some male patients may be motivated by the increased cancer risk, others may fear having a heart attack or stroke, and yet other patients might want to quit due to peripheral vascular disease that results in erectile dysfunction,” Fisher said. “Our patients are unique in what might motivate them to quit and so it [is] good to have another talking point to discuss with patients.”
When talking about smoking cessation, Fisher said he gives his patients plenty of latitude to decide which methods may work best for them.
“I discuss all the options available and let the patient choose the preferred treatment. It is important to not only discuss the variety of pharmacological options, such as patches, gum, nasal sprays and pills, but also the importance of behavior change. I also will usually supply the patient with my state’s tobacco quit line so that there is access to a nicotine counseling specialist.
“Smoking cessation takes some planning on the part of the patient. I think that the treatment that is most effective is the one that the patient wants to try when ready and not one that they feel pressured into trying.”
Fisher added that he is open with patients about the challenges they may face, and that patients should not feel discouraged if they are unable to quit smoking after the first try.
“I am very honest with patients about how addictive tobacco is. I want them to understand that it is not easy to quit and that most people require several attempts to be successful. I don’t want patients to give up with a setback because there is always something to learn with each attempt at quitting.”
Aside from quitting smoking, Fisher said he often suggests other ways that patients can reduce fracture risk.
“I go back to the basics, as I believe that some lifestyle medicine advice can really be impactful,” Fisher said. It is important for bone health to get a well-balanced diet that incorporates calcium from dairy and other sources and that limits pop intake. Weight resistance training several times a week is important to help maintain muscle mass. Weightbearing exercise such as aerobics, biking and racquet sports can help build bone strength as well. It is important to also limit alcohol intake.”
For AAFP members interested in learning more about tobacco cessation, Fisher pointed to a variety of articles and resources for clinicians and patients available at AAFP.org, as well as the Academy’s patient-centric site, familydoctor.org. He also recommended the CDC’s 1-800-QUIT-NOW webpage, which contains additional information and patient resources.