Dietary insulin index and insulin load in relation to glioma: findings from a case–control study

ABSTRACT

Background

Although hyperinsulinemia is assumed to be involved in brain carcinogenesis, data on the link between dietary insulin index (DII) and dietary insulin load (DIL) and risk of glioma are lacking.

Objective

The current study aimed to investigate the relation between DII and DIL and risk of glioma in a case–control study among Iranian adults.

Methods

In this hospital-based case–control study, 128 pathologically confirmed cases of glioma and 256 age and sex-matched controls were enrolled. Dietary intakes of study participants were assessed using a validated Block-format 123-item semi-quantitative FFQ. DII and DIL were computed using a published food insulin index (FII) data.

Results

A significant positive association was found between DIL and glioma (OR: 3.56; 95% CI: 1.85–6.58, P < 0.001); such that after controlling for potential confounders, participants in the highest quartile of DIL had 2.95 times greater odds of glioma than those in the lowest quartile (OR: 2.95; 95% CI: 1.40–6.24, P_trend=0.006). Furthermore, we observed a significant positive association between DII and glioma (OR: 2.65; 95% CI: 1.43–4.93, P_trend= 0.001). This association remained significant even after considering energy intake (OR: 2.66; 95% CI: 1.43–4.95, P_trend = 0.001). However, when further potential confounders were taken into account, this relationship became non-significant (OR: 1.87; 95% CI: 0.92–3.80, P_trend = 0.03), despite a significant trend of increased odds ratios (P = 0.03).

Conclusions

In conclusion, we found a significant positive association between DIL and odds of glioma. DII was not significantly associated with odds of glioma after controlling for confounders.

KEYWORDS:

• Brain tumour
• case–control study
• dietary insulin index
• dietary insulin load
• FFQ
• food insulin index
• glioma
• insulin

Acknowledgments

The authors would like to thank authorities in Tehran University of Medical Sciences for financial support of the study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The study was financially supported by National Institute for Medical Research Development (grant number 977421).

Notes on contributors

Javad Anjom-Shoae

Javad Anjom-Shoae has obtained his Bachelor of Science (Nutrition Science and Dietetics) from Isfahan University of Medical Sciences, Isfahan, in 2016 and is currently a M.Sc. candidate at the Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran. His research interest lies in investigating diet-disease associations, specifically with the aim of maintenance of physical and mental well-being as well as the prevention of chronic diseases such as cardiovascular disease.

Mehdi Shayanfar

Mehdi Shayanfar is a research associate at the Department of Clinical Nutrition and Dietetics, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Minoo Mohammad-Shirazi

Minoo Mohammad-Shirazi is a research associate at the Department of Clinical Nutrition and Dietetics, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Omid Sadeghi

Omid Sadeghi is a Ph.D. candidate at the Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.

Giuve Sharifi

Giuve Sharifi is a research associate at the Department of Neurosurgery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Fereydoun Siassi

Fereydoun Siassi is a professor (full) at the Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.

Ahmad Esmaillzadeh

Ahmad Esmaillzadeh is a professor (full) at the Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran. His research goal is to develop and validate dietary strategies that effectively protect against obesity-associated chronic conditions, including metabolic syndrome, cardiovascular disease, gastrointestinal disease, psychological disorders, and different cancers.