Kidney Week

Abstract: FR-PO239

Net Gastrointestinal Alkali Absorption and Risk of Bone Disease

Session Information

• Mineral Bone Disease: Transplant and Kidney Stones
  October 25, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Bone and Mineral Metabolism

• 502 Bone and Mineral Metabolism: Clinical

Authors

• Ganesan, Calyani, Stanford University School of Medicine, Stanford, California, United States

Calyani Ganesan, MD

• Curhan, Gary C., Brigham and Women's Hospital, Boston, Massachusetts, United States

Gary C. Curhan, MD, ScD, FASN

• Ferraro, Pietro Manuel, Universita degli Studi di Verona, Verona, Veneto, Italy

Pietro Manuel Ferraro, MD, MS, PhD

• Paik, Julie M., Brigham and Women's Hospital, Boston, Massachusetts, United States

Julie M. Paik, MD, MPH

Background

Studies suggest that the modern Western diet provides a net acid load to the body and may negatively impact bone health. The role of dietary alkali in neutralizing this acid load and mitigating acid-related injury to bone remains unknown. The objective of this study was to investigate the association between gastrointestinal alkali absorption and bone disease.

Methods

We analyzed the association between net gastrointestinal alkali absorption (NGIA) and incident bone disease using three large cohorts - the Health Professionals Follow-up Study, Nurses’ Health Study I and Nurses’ Health Study II. We estimated NGIA according to the Oh equation using 24-hour urine measurements. The primary composite outcome of bone disease included osteopenia, osteoporosis and fracture (hip, vertebral and wrist). We performed Cox proportional hazards regression to identify the incident risk of bone disease by level of NGIA. We adjusted for factors that impact bone health such as age, sex, body mass index, and smoking status.

Results

We included data from 4,592 participants (1,023 men and 3,569 women). A total of 1,226 bone disease cases were confirmed. The incidence rate of bone disease was 1,922 per 100,000 person-years. The mean (SD) NGIA for quintile 1 was 4 (9.4), for quintile 2 was 19.6 (5.1), for quintile 3 was 29.8 (5.2), for quintile 4 was 41 (6.6) and for quintile 5 was 64.1 (15.9). When compared with the lowest quintile of NGIA, the adjusted HRs of bone disease were 1.12 (95% CI 0.90, 1.35) for quintile 2 of NGIA, 1.07 (0.88, 1.29) for quintile 3, 1.10 (0.91, 1.33) for quintile 4 and 1.27 (1.06, 1.53) for quintile 5 (p-trend=0.20). Results did not materially differ by sex. Factors associated with an increased risk of bone disease included body mass index < 21 kg/m² (HR 1.7; 95% CI 1.38, 20.8) and current smoking status (HR 1.50; 95% CI 1.17, 1.93).

Conclusion

When compared with the lowest levels of NGIA, there was no significant association between moderate levels of NGIA and the risk of bone disease; however there was a significant association between the highest levels of NGIA and the risk of bone disease. The heterogeneity in the strength of the association between moderate to high levels of NGIA and bone disease suggests that dietary alkali likely has a modest effect on bone health when compared to other risk factors such as low body mass index and smoking status.

Funding

• NIDDK Support