RiteeshGrandhi/sciclaimeval-shared-task huggingface dataset:
Results
The study included 1,396 participants, with a mean age of 19.6 ±1.2 years, and 58.6% female, of whom 599 (42.9%) reported suboptimal SRH and 390 (27.9%) reported prolonged sleep latency (≥30 min). Table 1 presents the basic characteristics of the participants. Participants with longer sleep latency had a higher percentage of suboptimal SRH, evening-type chronotype, and slept less than 6 h per night compared to those with sleep latency of less than 10 min ( P < 0.05). However, there were no significant differences in gender, residence, single child, parental education, BMI, afternoon nap, sitting time, and physical activity among these groups.

Notes:

Values are mean (SD) or median ( P 25 , P 75 ) for continuous variables and frequency (percentage) for categorical variables.

Table 2 presents the multivariable-adjusted ORs of suboptimal SRH associated with sleep latency. Compared to participants with sleep latency of less than 10 min, those with longer sleep latency demonstrated an increased risk of suboptimal SRH. After adjusting for gender, grade, residence, parental education, and single child, the ORs (95% CIs ) for those with sleep latency of 10–19 min, 20–29 min, and ≥30 min were 1.50 (1.11, 2.04), 2.05 (1.44, 2.92), and 2.46 (1.80, 3.36), respectively. With further adjustment for BMI, afternoon nap, midnight snack habit, sitting time, physical activity, sleep duration, and chronotype, the adjusted ORs (95% CIs ) were 1.48 (1.07, 2.05), 2.03 (1.39, 2.97), and 2.12 (1.52, 2.96) ( P for trend<0.001).

Notes:

We also investigated the combined effect of sleep latency and midnight snack habit on suboptimal SRH ( Figure 2 ). Sleep latency was categorized into four groups (≤10 min, 10–19 min, 20–29 min, and ≥30 min). We found that individuals with long-sleep latency and a midnight snack habit had higher odds of suboptimal SRH than those without the habit and with sleep latency less than 10 min (fully-adjusted OR : 4.50; 95% CI: [2.43–8.33]).

We conducted stratified analyses to investigate the association between sleep latency and suboptimal SRH among subgroups categorized by lifestyle factors, including afternoon nap, midnight snack habit, BMI, sleep duration, and chronotype ( Table 3 ). Our findings indicated that longer sleep latency was consistently associated with higher odds of suboptimal SRH in most subgroups, although some associations did not achieve statistical significance ( P for interaction > 0.05).

Notes:

We conducted sensitivity analyses to assess the robustness of the relationship between sleep latency and suboptimal SRH. We included only non-smokers ( n = 1,289) and found no changes in our results ( Table 4 ). We also analyzed only non-drinkers and the results were largely unchanged. After including sleep latency as a continuous variable in the logistic regression model, the results were found to be consistent with our initial findings ( Table 2 ). Furthermore, when sleep latency was reclassified into three groups for analysis, the findings aligned generally agreement with the main results ( Table 4 ).

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Conclusions
Our study demonstrated that poor SRH is common among university students in China and revealed a significant association between sleep latency and suboptimal SRH in medical students. Compared to sleep latency of less than 10 min, longer sleep latency (≥30 min) increased the odds of suboptimal SRH. Our findings underscore the importance of addressing sleep latency to enhance the health of medical students. The health of medical students with prolonged sleep latency and midnight snack habit warrants particular attention. Future research is needed to elucidate the mechanisms linking sleep latency and health.
Figure 1: Bland–Altman (difference vs average) of diary-reported sleep latency vs questionnaire-reported sleep latency.

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DOI: 10.7717/peerj.19459/fig-1
Figure 2: The joint effect of sleep latency and midnight snack habit on suboptimal self-rated health among medical students.
The model was adjusted for all the variables in MV2.

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DOI: 10.7717/peerj.19459/fig-2
Characteristics of study participants.
Association between sleep latency and odds ratios (95% CIs) of suboptimal self-rated health among medical students.
Sleep latency and suboptimal self-rated health, stratified analysis by lifestyles.
Sensitivity analyses on associations between sleep latency and suboptimal self-rated health.