The researchers believe the caffeine found in many soft drinks can be considered a risk factor for osteoporosis. “Soft drinks may contain phosphoric acid, which has shown to interfere with calcium absorption and to contribute to imbalances that lead to additional loss of calcium. It has also been suggested that the high fructose corn syrup used to sweeten carbonated beverages may negatively affect bone,” adds Lu.
The main finding is that in general, the more sugary soda men drink, the greater the risk that knee osteoarthritis will get worse. If you’re thinking that is because the calories in soda may contribute to being overweight or obese — a known risk factor for knee osteoarthritis — think again.
Much to the researchers’ surprise, the link between knee osteoarthritis and sugary soft drinks could not solely be explained by weight, Lu says.
“We very carefully [took into account] weight in the statistical analysis. We controlled not only for the general categories of overweight and obesity, but also for patients’ specific body-mass indices, or BMIs,” he says.
When the men were divided into obese and non-obese, the link between sugary drinks and worse knee damage held true only in the non-obese men.
This suggests that soft drinks worsen knee osteoarthritis independently of the wear and tear on the joints caused by carrying around excess weight, Lu says.