Association between healthy eating index and sleep quality and duration in older adults: findings from the NeLSA cohort Study, Iran

Poor sleep and malnutrition are prevalent issues among older adults, contributing to negative outcomes such as depression, sarcopenia, and reduced quality of life. A bidirectional relationship has been proposed between diet and sleep. This study aimed to examine the association between the Healthy Eating Index (HEI) and both sleep quality and duration in older adults.

This cross-sectional analysis was conducted using baseline data from the Neyshabur Elderly Longitudinal Study (NeLSA, 2016-2022), including 2,026 adults aged ≥ 60. Dietary data were collected via a validated food frequency questionnaire, and HEI-2015 scores were calculated. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI), with a score > 5 indicating poor sleep quality. Sleep duration was self-reported and categorized as adequate (≥ 7 h) or insufficient (< 7 h). Multivariable logistic regression was used to assess associations between HEI quartiles and sleep outcomes, adjusting for demographics, BMI, smoking, education, and chronic diseases.

Participants had a mean age of 69.1 ± 7.6 years; 55.5% were women. Women reported poorer sleep quality and shorter sleep duration than men (P < 0.001). There was no statistically significant association between HEI and sleep quality or duration in the overall population or by gender (P > 0.05). However, a borderline non-significant inverse association was observed between HEI and insufficient sleep duration in older women. (Q4 vs. Q1, OR: 0.709; 95% CI: 0.502-1.003; P = 0.052).

Higher HEI scores were not independently associated with sleep quality or duration among older adults. Although higher diet quality showed a non-significant inverse association between better sleep in women, the relationship may be influenced by other health-related factors. Further longitudinal and interventional studies are recommended.