Does menopause increase the risk of developing kidney stones?

Menopause and Kidney Stone Risk

Menopause is associated with a higher risk of incident kidney stones, with postmenopausal women having approximately 27% increased risk compared to premenopausal women. 1

Relationship Between Menopause and Kidney Stone Risk

• Postmenopausal status is independently associated with higher risk of kidney stone formation (multivariate adjusted relative risk 1.27; 95% CI 1.08-1.46) compared to premenopausal status 1
• Both natural menopause (RR 1.27; 95% CI 1.09-1.48) and surgical menopause (RR 1.43; 95% CI 1.19-1.73) are independently associated with increased kidney stone risk 1
• The protective effect of estrogen against kidney stone formation diminishes after menopause, which may explain the increased risk in postmenopausal women 2

Physiological Mechanisms

• Menopause leads to significant changes in urine composition that may promote stone formation:

  • Lower urinary calcium, citrate, phosphorus, and uric acid excretion 1
  • Higher urine volume (which may be compensatory) 1
  • Lower urinary saturation of stone-forming salts in premenopausal women compared to men, which may explain the lower risk of stone formation in premenopausal women 2

• Estrogen appears to have protective effects against kidney stone formation through:

  • Reducing urinary calcium excretion 2
  • Lowering calcium oxalate saturation in urine 2
  • These protective effects are lost during menopause 2, 1

Impact of Hormone Replacement Therapy

• Estrogen-treated postmenopausal women have lower 24-hour urinary calcium (155 ± 62 vs 193 ± 90 mg/day) and lower calcium oxalate saturation (5.07 ± 2.27 vs 6.48 ± 3.44) compared to untreated postmenopausal women 2
• However, neither current nor past hormone replacement therapy use has been significantly associated with kidney stone risk in large observational studies 1
• Meta-analysis data suggests no significant association between postmenopausal hormone therapy and the risk of nephrolithiasis (pooled relative risk 0.91; 95% CI 0.72-1.14) 3

Additional Risk Factors in Postmenopausal Women

• Multivariate risk factors for kidney stones in postmenopausal women include:
  • History of hypertension 4
  • Low dietary intake of magnesium 4
  • Low use of calcium supplements 4
• Women with chronic kidney disease experience menopause at a younger age (median 47 years vs 50-51 years in women with normal renal function), which may further increase their kidney stone risk 5, 6

Clinical Implications

• Regular assessment of kidney stone risk factors is essential for postmenopausal women 5
• Adequate fluid intake to achieve urine volume >2.5 liters daily is recommended to prevent new stones 7
• Reduced sodium intake is advised to decrease the risk of stone formation 7
• Supplemental calcium intake >500 mg/day may be inversely associated with stone occurrence in postmenopausal women 4

Pitfalls and Caveats

• The relationship between menopause and kidney stones may be confounded by age-related changes in metabolism and diet 1, 8
• Surgical menopause appears to carry a higher risk for kidney stone formation than natural menopause 1, 8
• While hormone replacement therapy shows some beneficial effects on urinary parameters, it is not currently recommended solely for kidney stone prevention 2, 1
• The impact of obesity on kidney stone risk is particularly pronounced in females 7