Dr Louisa Lam, deputy dean of the School of Nursing and Healthcare Professions at Federation University in Australia, said she had “doubts with the analysis” made recently by researchers at Tulane University in New Orleans into the use of glucosamine, a naturally occurring component of joint cartilage.
They found that the regular use of glucosamine supplements, which are normally taken to help joint pain, could lead to a 15% reduction in the risk of cardiovascular disease events overall. The benefit among smokers was more than double that of non smokers.
Though the study is observational, meaning it cannot show cause and effect, the researchers behind it say this link could be explained by the effects of glucosamine on inflammation, which plays a role in both cardiovascular disease and arthritis.
"There is so much controversy surrounding the effects of glucosamine and vitamin supplements in general, and I do have doubts with the analysis. There is lots of research evidence that supports my doubt,” Lam said.
Since the study looked at over 466,000 subjects, it is “easy to find some statistical significance in ‘things’ the researchers want,” she continued. “Huge samples can make the insignificant significant.”
She called on the researchers behind it to investigate the relationship between other supplements and cardiovascular events and death.
“The authors should provide information on other supplements as comparisons. A Yes and No answer on the use of glucosamine is insufficient; we need dose and length information.
“I have doubt on the reported result in relation to the link between glucosamine supplement and lower risks of cardiovascular events.”
Meanwhile, Associate Professor Ken Harvey, of the school of Public Health and Preventative Medicine at Monash University, suggested the hypothesis behind the glucosamine study was “at best dubious” and could verge on the “misleading”.
“The results were expressed as relative risk, not absolute risk,” Dr Harvey said. "This is potentially misleading: figures on absolute risk (CVD events, deaths, etc, per 1000 patients per year in glucosamine users compared to non-users) should also have been given.
“Glucosamine is no longer recommended for osteoarthritis, thus it is unlikely that this study will be replicated again. A large-scale controlled clinical trial to test what is at best a dubious hypothesis is unlikely to get up.”
“Association of habitual glucosamine use with risk of cardiovascular disease: prospective study in UK Biobank”
Authors: Hao Ma, et al.