Background/rationale
Multiple myeloma (MM) is one of the most common blood cancers. Despite lengthened survival with recent advances in therapies, it remains essentially incurable. Understanding the influence of common modifiable risk factors on MM risk is necessary to inform prevention of this disease. We aimed to assess the association of dietary pattern, fish consumption, and lifestyle index score, with MM risk.
Methods
Histologically confirmed, incident cases of MM (n=746) were recruited primarily via cancer registries in Victoria and NSW, Australia. Controls (n=706) were siblings or spouses of cases. Unconditional logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI) for the association between dietary exposures and MM risk. Multiple imputation using chained equations was utilised to handle missing data.
Results
Higher scores on a modified version of the Alternative Healthy Eating Index-2010 (mAHEI: OR=0.88, 95%CI=0.78-0.98 and the healthful plant-based dietary index (hDPI: OR=0.91, 95%CI=0.81-1.02) were associated with reduced risk of MM. Higher scores on empirical dietary inflammatory pattern (EDIP: OR=1.20, 95%CI=1.07-1.35) and empirical dietary indices for hyperinsulinaemia (EDIH: OR=1.15, 95%CI=1.02-1.31) and insulin resistance (EDIR: OR=1.21, 95%CI=1.08-1.37) were associated with increased risk of MM. There was no clear evidence of association with MM risk for oily fish consumption (OR=0.96, 95%CI=0.85-1.08), total fish consumption (OR=0.95, 95%CI=0.85-1.07) or a healthy lifestyle index (OR=0.94, 95%CI=0.84-1.05).
Conclusion
Adherence to a higher quality diet, or healthy plant-based diet, might reduce MM risk. Adherence to dietary patterns with the potential to increase insulin levels, insulin resistance, or promote inflammation, could increase risk of MM. Future research to confirm findings and investigate underlying mechanisms is warranted.