Association between circadian rhythm and sleep quality among nursing interns: A latent profile and moderation analysis

Abstract

Background: Disturbances in circadian rhythms are common among night-shift workers and result in poor sleep quality. Nevertheless, the heterogeneity of circadian rhythms and their relationship with sleep quality is less explored in nursing interns. Therefore, we aimed to identify the latent subtypes of circadian rhythm, explore their relationship with sleep quality, and evaluate their moderating role between perceived stress and sleep quality in nursing interns.

Materials and methods: In all, 452 nursing interns were recruited between October 2020 and January 2021 from Be Resilient to Nursing Career (BRNC), which is a multicenter, prospective cohort of a career growth program for nursing students. They were assessed using the 10-item Chinese Perceived Stress Scale, Circadian Type Inventory, and Pittsburgh Sleep Quality Index. Latent profile analysis and moderation analysis were performed.

Results: Overall, 72.3% of the nursing interns reported poor sleep quality. We identified three latent subtypes of circadian rhythms, namely, Vigorousness (40.1%), Inadaptability (18.6%), and Flexibility (41.1%). Females (OR = 1.97, 95% Cl: 1.01-3.83, P = 0.047) with normal body mass index (OR = 1.62, 95% CI: 0.95-2.76, P = 0.078) were prone to Flexibility. Circadian rhythm types significantly moderated the association between perceived stress and sleep quality (P < 0.05).

Conclusion: Nursing interns suffer from poor sleep. There exists heterogeneity of circadian rhythm subtypes in nursing interns, and attention should be paid to those with Inadaptability type. The association between perceived stress and sleep quality is significantly moderated by circadian rhythm subtypes.

Keywords: Be Resilient to Nursing Career (BRNC); circadian rhythm; latent profile analysis; moderation analysis; nursing interns; perceived stress; sleep quality.

FIGURE 1

The hypothetical framework for circadian rhythms and sleep quality in nursing interns.

FIGURE 2

Spearman correlation Heatmap among perceived stress, circadian rhythms, and sleep quality (A), and curve line regression of the above three variables (B–D).

FIGURE 3

Fitting index and group size of latent profile analysis models and logistic regression results for predicting external features on the 3-class pattern. (A) Fitting index and group size of latent profile analysis models. Bold figures highlight the selected class solution. LL, Log-likelihood; AIC, Akaibe information criterion; BIC, Bayesian information criterion; aBIC, adjusted BIC; LMR, Lo, Mendell, and Rubin likelihood ratio test; C1, vigorous; C2, inadaptability; C3, flexibility. (B) Parameters for the final three-class patterns. FR, flexible/rigid; LV, languid/vigorous. (C) Univariate and multivariate logistic regression results for predicting external features on the 3-class pattern. BMI, body mass index; OR, Odds ratio; CI, confidence interval. Bold figures highlight statistically significant in the multivariate logistic regression.

FIGURE 4

ANOVA comparison of PQSI scores across LPA-based groups and post hoc comparison by Bayesian factor analysis. (A) LPA-based differences on PSQI scores were estimated by Bayesian Factor. V, Vigorous group; F, flexibility group; I, inadaptability group; SD, standard deviation; MD, mean difference; BF, Bayes Factor; η², eta squared represents the explained unique variance of a dependent variable by three homogenous subgroups. (B) ANOVA model averaged psterior distribution. (C) Inferential plots for Bayesian factor analysis.

FIGURE 5

The effect of circadian rhythm subtypes on sleep quality by stratified analysis. Stratified associations between circadian rhythm types and sleep quality by physiological and environmental factors. Analyses were adjusted for covariates gander, the habit of drinking coffee, regularity of diet, night shifts, BMI, PSS when they were not the strata variables. OR, odds ratio; CI, confidence interval. Bold figures highlight statistically significant in the strata variables.

FIGURE 6

The moderating effect of circadian rhythm types between perceived stress and sleep quality. (A) Moderating role of circadian rhythm types in the association between perceived stress and sleep quantity. Regularity of diet was adjusted for each model. Independent variables were centered before analysis. (B) Simple slope plot of the interaction between circadian rhythm types and perceived stress on sleep quality.