Glucosamine with chondroitin is a widely used combination supplement used to treat osteoarthritis and joint pain and it is available without a prescription in the United States. Both glucosamine and chondroitin are natural compounds found in cartilage, and can take as a dietary supplement to treat osteoarthritis and joint pain.
Several large clinical trials have compared glucosamine/chondroitin to either placebo or celecoxib but have not demonstrated significant improvement in arthritis pain, although the glucosamine/chondroitin exhibited no long-term safety issues. However, 2 recent large cohort studies, 1 in the state of Washington and 1 in the United Kingdom, have found somewhat surprising beneficial effects on a different outcome, long-term mortality.
In this study, Dr. Dana King, study lead and research partner Jun Xiang a WVU health data analyst, sought to investigate the association of daily use of glucosamine/chondroitin with cardiovascular and overall mortality in a large US cohort, making sure to take into account demographic and disease variables that might influence the association.
Combined data from 16,686 participants in the National Health and Nutrition Examination Survey (NHANES) 1999 to 2010, merged with the 2015 Public-use Linked Mortality File. Cox proportional hazards models were conducted for both CVD and all-cause mortality.
After controlling for various factors like gender, age, smoking status and activity level the findings showed that taking a glucosamine/chondroitin supplements every day for one year or longer was associated with a 39% reduction in all-cause mortality. Regular consumption of this supplement was also linked to a 65% reduction in cardiovascular-related deaths:
In the study sample, there were 658 (3.94%) participants who had been taking glucosamine/chondroitin for a year or longer. During follow-up with a median of 107 months, there were 3366 total deaths (20.17%); 674 (20.02%) were due to CVD. Respondents taking glucosamine/chondroitin were less likely to have CVD mortality (hazard ratio [HR] = 0.51; 95% CI, 0.28-0.92). After controlling for age, use was associated with a 39% reduction in all-cause (HR = 0.61; 95% CI, 0.49–0.77) and 65% reduction (HR = 0.35; 95% CI, 0.20–0.61) in CVD mortality. Multivariable-adjusted HR showed that the association was maintained after adjustment for age, sex, race, education, smoking status, and physical activity (all-cause mortality, HR = 0.73; 95% CI, 0.57–0.93; CVD mortality, HR = 0.42; 95% CI, 0.23–0.75).
Based on their findings the researchers concluded that, “Regular intake of glucosamine/chondroitin is associated with lower all-cause and CVD mortality in a national US cohort and the findings are consistent with previous studies in other populations.” Adding that “In conclusion, regular consumption of glucosamine/chondroitin seems to be significantly associated with lower overall and cardiovascular mortality. Given the strength of the association, a 27% lower likelihood of overall mortality and a 58% lower likelihood of cardiovascular death.” Making note that additional research is needed to confirm their findings: “Prospective studies to confirm the link may be warranted.”
This study was not without limitations with the researchers noting that: “Limitations include that this is a cohort study and not a randomized trial; thus, the individuals taking glucosamine/chondroitin were self-selected and not randomized, introducing possible bias. Further, the amount and consistency of supplement intake was not tracked for adherence throughout the follow-up period. We attempted to mitigate this impact by choosing only people who had been taking the supplement for a year or more, to select consistent long-term users, and in the current study, we ended up with a lower proportion of users than in the UK study. In addition, people could have been taking other supplements that could have accounted for some of the findings, but there are too many supplements to control for all them. In addition, the survey is by self-report survey by the respondent for all questions including regarding whether they had other medical conditions. Finally, another possible limitation is that the respondents are mostly non-Hispanic whites, however, we controlled for race in the analyses.”
“Does this mean that if you get off work at five o’clock one day, you should just skip the gym, and take a glucosamine pill and go home instead? That’s not what we suggest. Keep exercising, but the thought that taking a pill would also be beneficial is intriguing,” says Dr. King who is a professor and chair of the Department of Family Medicine at West Virginia University.
Dr. King explains that this is an epidemiological study rather than a clinical trial, as such it is not able to offer definitive proof that glucosamine/chondroitin makes death less likely, but he does call the results “encouraging.”
“In my view, it’s important that people know about this, so they can discuss the findings with their doctor and make an informed choice. Glucosamine is over the counter, so it is readily available,” adds Dr. King.
