Body Composition

Association among Dietary Inflammatory Index, sleep quality and nutritional status in fixed daytime and rotating shift workers.

TL;DR

In 52 male defense-industry workers, rotating shift workers had higher energy and several nutrient intakes than fixed daytime workers but similar DII scores, and although higher DII correlated with poorer sleep quality, this association was no longer significant after adjusting for confounders.

Key Findings

Rotating shift workers had significantly higher total energy intake than fixed daytime workers.

  • Cross-sectional study of 52 male workers at a defense industry factory in Ankara, Türkiye, in fixed daytime or rotating shift schedules.
  • Dietary intake was assessed with 24-h dietary recalls on three non-consecutive days.
  • The abstract reports the difference as significant at p < 0.05.

Rotating shift workers had higher intakes of fructose, total fat, saturated and monounsaturated fatty acids, and cholesterol than fixed daytime workers.

  • Macronutrient intakes were calculated from three 24-h recalls.
  • Differences were reported as significant at p < 0.05.
  • The abstract does not give group means for these nutrients.

Rotating shift workers had higher intakes of several micronutrients, including vitamin A, folate, iron, calcium, and phosphorus.

  • Micronutrient intakes were calculated from three non-consecutive 24-h recalls.
  • Differences were significant at p < 0.05 compared with fixed daytime workers.

Mean Dietary Inflammatory Index (DII) scores did not differ significantly between fixed daytime and rotating shift workers.

  • Fixed daytime: 0.2 ± 1.86; rotating shift: -0.2 ± 2.25.
  • DII was computed from dietary recall data to assess the inflammatory potential of the diet.
  • Both groups had mean scores near zero, with wide variability.

Higher DII scores were positively correlated with poorer global sleep quality (PSQI score).

  • Correlation between DII and global PSQI: r = 0.278, p = 0.046.
  • Sleep quality was assessed with the Pittsburgh Sleep Quality Index.
  • Higher PSQI scores indicate worse sleep quality.

DII scores were positively correlated with the PSQI sleep duration and daytime dysfunction component scores.

  • Sleep duration component: r = 0.319, p = 0.021.
  • Daytime dysfunction component: r = 0.287, p = 0.039.

The association between DII and overall sleep quality was no longer statistically significant after adjustment for confounders.

  • Adjustment covariates were age, BMI, smoking status, physical activity, and work schedule.
  • This suggests the unadjusted correlation may be partly explained by these factors.

The authors conclude that dietary habits, pro-inflammatory dietary patterns, and poor sleep quality may be co-existing factors associated with metabolic risk.

  • Anthropometric, body composition, blood pressure, and biochemical measures (glucose, lipid profile, CRP, homocysteine) were collected using standardised protocols.
  • The authors suggest that addressing these factors may contribute to better overall metabolic health.
  • The design is cross-sectional with a small all-male sample (n = 52).

What This Means

This study looked at 52 men working at a defense factory in Türkiye, some on fixed daytime schedules and some on rotating shifts. The researchers compared what they ate (using three 24-hour food recalls), how inflammatory their diets were (using the Dietary Inflammatory Index, or DII), and how well they slept (using the Pittsburgh Sleep Quality Index). They also took body measurements and blood tests. Rotating shift workers ate more overall, including more fat, saturated fat, cholesterol, and fructose, and also more of certain vitamins and minerals such as vitamin A, folate, iron, calcium, and phosphorus. However, the inflammatory potential of the diet, as measured by DII, was not meaningfully different between the two groups. Across all participants, a more inflammatory diet was linked with worse sleep, including shorter sleep duration and more daytime dysfunction. But once factors such as age, BMI, smoking, physical activity, and work schedule were taken into account, the link between DII and overall sleep quality was no longer statistically significant. This research suggests that diet and sleep problems may occur together in shift workers, but it cannot show that one causes the other. The study was small, included only men from one workplace, and measured everything at a single point in time, so the findings should be treated cautiously.

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Citation

S&#xfc;nb&#xfc;l &, T&#xfc;rker P. (2026). Association among Dietary Inflammatory Index, sleep quality and nutritional status in fixed daytime and rotating shift workers.. PloS one. https://doi.org/10.1371/journal.pone.0360075