The association between the dietary inflammatory index and multiple myeloma: a case-control study

The dietary inflammatory index (DII) is a common grading system for diet inflammatory potential. Recent investigations link DII to hematopoietic malignancies. However, the relationship between DII and Multiple myeloma (MM) is unknown. DII and MM were examined in a present case-control study of Iranian adults. This case-controlstudy was conducted on adults aged 20 to 75 years, selecting 149 cases with newly diagnosed multiple myeloma and 359 healthy individuals. Dietary assessment was conducted using a validated semi-quantitative food frequency questionnaire (FFQ) including 154 items, and energy-adjusted DII scores were calculated to determine the level of inflammatory properties in each individual's diet using 29 dietary parameters. Conditional logistic regression models were used to investigate the relationship between DII and MM. The case group participating in the study was on average 54 years old and mostly male (52.3%). After adjusting for age, sex, and energy intake, we found that individuals with the highest DII scores were significantly less likely to have MM compared to those with the lowest scores (OR: 0.02; 95% CI 0.01, 0.08). Additional adjustment with other confounders confirmed this association (OR: 0.03; 95% CI 0.01, 0.13). This association did not change significantly with further adjustment for BMI (OR: 0.04; 95% CI 0.01, 0.14). In conclusion, our research showed that a pro-inflammatory diet was associated with a significantly higher risk of MM. If our findings are confirmed in other large studies, these data will provide personalized approaches for MM patients, particularly for physicians and registered cancer dietitians.