With aging, men and women develop a mild and progressive metabolic acidosis. This occurs as a result of declining renal function and ingestion of acid-producing diets. There is extensive evidence that severe metabolic acidosis causes bone and muscle loss, but the impact of the chronic, mild acidosis on bone and muscle in older individuals has not been established. In a recent study, administration of a single dose of bicarbonate daily for 3 months significantly reduced urinary excretion of N-telopeptide (NTX), a marker of bone resorption and urinary nitrogen, a marker of muscle wasting and improved muscle performance in the women but not the men. These and other data support a potential role for bicarbonate as a means of reducing the musculoskeletal declines that lead to extensive morbidity and mortality in the elderly. Before proceeding to a long-term bicarbonate intervention study, however, it is important to identify the dose of bicarbonate most likely to be optimal and to characterize the subjects who benefit most from it. This double blind, placebo controlled, dose-finding study will evaluate the effects of placebo and two doses of bicarbonate on urinary NTX and nitrogen excretion and on lower extremity performance over a 3 month period in 138 men and 138 women, age 60 and older. Changes in urinary excretion of NTX and nitrogen and in selected measures of lower extremity performance will be compared across the three groups. The safety and tolerability of the interventions will also be evaluated. This investigation should provide needed information on the appropriate dosing regimen for men and women and on the study population that should be enrolled in a future bicarbonate intervention trial to assess the long-term effects of this simple, low cost intervention on important clinical outcomes including rates of loss in bone and muscle mass, falls, and fractures.
This dose-finding study will evaluate the effects of placebo and two doses of bicarbonate on urinary NTX and nitrogen excretion and on lower extremity performance over a three month period. The lower dose is similar to the dose shown in our recent trial to be effective. This study is a double blind, randomized, placebo-controlled, parallel-group trial in which 138 healthy men and 138 women, age 60 and older, will take potassium bicarbonate in doses of 1.0 or 1.5 mmol/kg of body weight or placebo daily for three months. Changes in urinary excretion of NTX and nitrogen and in measures of lower extremity performance will be compared across the three groups. The safety and tolerability of the interventions will also be evaluated. This investigation should provide needed information on the appropriate dosing regimen and on the study population that should be enrolled in a future bicarbonate intervention trial to assess the long-term effects of this simple, low cost intervention on important clinical outcomes including rates of loss in bone and muscle mass, falls, and fractures.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
244
potassium bicarbonate in dose of 1.0 mmol/kg per day, given in three even daily doses after meals with a full glass of water
potassium bicarbonate in dose of 1.5 mmol/kg per day, given in three even daily doses after meals with a full glass of water
microcrystalline cellulose
Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University
Boston, Massachusetts, United States
The Dose of Potassium Bicarbonate Needed for Maximal Suppression of 24-hr Urinary N-telopeptide
Describe and compare changes in urinary N-telopeptide (NTX) across the placebo and Potassium Bicarbonate (KHCO3) doses.
Time frame: 84 days
Co-primary Aim - to Identify the Dose of KHCO3 Needed for Maximal Suppression of 24-hr Urinary Nitrogen
Describe and compare changes in 24-hour urinary nitrogen in the low and high dose and KHCO3 group and in placebo.
Time frame: 84 days
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