Low-sodium diets up osteoporosis risk

Low levels of sodium intake appear to worsen bone mineral density (BMD) and aggravate the risk of osteoporosis, a recent study has found.

Researchers conducted a population-based cross-sectional analysis of 3,869 participants, in whom 24-hour urinary sodium excretion (e24hUNaE) was measured using the Tanaka method and used as a surrogate indicator for sodium intake. Outcomes included BMD and incident osteoporosis.

In general, men had significantly greater sodium intake than women (mean, 2.3 vs 1.9 g/day; p<0.001). Linear regression analysis found that higher e24hUNaE was significantly associated with markers of systemic inflammation, including C-reactive protein (p=0.0442) and platelet (p<0.0001) levels. Meanwhile, sodium intake was only marginally associated with various measures of areal BMD.

Cox proportional hazard modelling further found a significant and inverse correlation between salt intake and osteoporosis risk. Even after controlling for confounders such as body mass index, kidney function, waist circumference, and blood markers, high e24UNaE suppressed the risk of osteoporosis by nearly 15 percent (adjusted hazard ratio, 0.859, 95 percent confidence interval, 0.751–0.982).

Moreover, Kaplan-Meier analysis paired with multiple Cox proportional models showed that osteoporosis-free survival was significantly lower among participants belonging to the lowest e24hUNaE quartile.

“This study demonstrated that a lower sodium diet below 2 g per day was an independent predictor for developing incipient osteoporosis,” the researchers said. “Large population-based prospective epidemiologic studies are warranted to confirm these findings.”