Background/objectives The dietary inflammatory index (DII) is a tool to measure the diet’s inflammatory potential and has
been used with adults to predict low-grade inflammation. The present study aims to assess whether this dietary score predicts
low-grade inflammation in adolescents.
Subjects/methods The sample comprises 329 adolescents (55.9% girls), aged 12–18 years, from LabMed Physical Activity
Study. DII score was calculated based on a food-frequency questionnaire and categorized into tertiles. We collected blood
samples to determine the follow inflammatory biomarkers: C-reactive protein (CRP), interleukin-6 (IL-6), complement
component 3 (C3), and 4 (C4). In addition we calculated an overall inflammatory biomarker score. Odds ratios (OR) and
95% confidence intervals (95%CI) were computed from binary logistic regression models.
Results DII score, comparing first with third tertile, was positively associated with IL-6 in crude model (OR = 1.88, 95%
CI:1.09–3.24, ptrend = 0.011) and in fully adjusted (for biological and lifestyle variables) (OR = 3.38, 95%CI:1.24–9.20,
ptrend = 0.023). Also, DII score was positively associated with C4, when fully adjusted (OR = 3.12, 95%CI:1.21–8.10, ptrend
= 0.016). DII score was negatively associated with C3 in crude model, comparing first with second but not with third tertile,
and no significant associations in fully adjusted model were observed, although a trend was found (OR = 1.71, 95%
CI:0.63–4.66, ptrend = 0.044). No significant associations were observed between DII score and CRP. However, DII score
was positively associated with the overall inflammatory biomarker score, when fully adjusted (OR = 5.61, 95%
CI:2.00–15.78, ptrend = 0.002).
Conclusions DII score can be useful to assess the diet’s inflammatory potential and its association with low-grade inflammation in adolescents.
The authors gratefully acknowledged the participation
of all adolescents and their parents, teachers and schools of
the LabMed and Physical Activity Study, the cooperation of volunteer’s,
the Department of Hygiene and Epidemiology (University of
Porto) for the conversion food frequency questionnaire data into
nutrients, and the Research Centre in Physical Activity, Health and
Leisure (University of Porto) for the sponsoring the LabMed and
Physical Activity Study.
