To establish reference values for lung function test in Filipinos, 283 (130 males and 153 females) normal non-smoking (< 0.5 pack years), adults were studied using a body plethysmograph (Jaeger, West Germany). Spirometric indices were integrated from a pneumotachograph (linear at flows between 0-20 1/sec with ± 2% error). Spirometric performance and measurements followed the ATS Snowbird Workshop recommendations. Lung volumes and airway resistance (Raw) were taken from the average of three plethysmographic determinations.

Multiple linear regressions with backward elimination was done. The data obtained was regressed against independent variables of age height, weight, and body surface area for each sex.

Analysis of variance (ANOVA) of the regression equations for most parameters were significant at = 0.01. In a few parameters were significance was = 0.05. Only in Raw was the regression model not significant. The coefficient of determination (R) of our regression equations were low (<0.50). However, such low R have been observed in other predictions equations which have gained widespread acceptance, attesting to their clinical usefulness. Ninety five percent confidence interval was used to determine the lower limit of normal for FEV1 and FVC. Since the other parameters showed greater individual variability, cumulative percentiles of % of predicted were determine instead (Knudson 1977). For performance test, the 5th percentiles of % of predicted was computed. For lung volumes, the 5th and 95th percentiles were determined. For Raw, the 95th percentiles of the actual values was used. Since there were fewer subjects above the age of 60 years, the use of these equations is subject to this limitation.

Human ; Male ; Female ; Smoking ; Lung ; Analysis Of Variance ; Population

BACKGROUND AND OBJECTIVE

Due to their academic load, medical students are highly susceptible to stress. Stress is one of the factors that can alter sleep quality which may consequently affect the cognitive performance of medical students. There has been a lack of published local literature that looks into the association between stress and sleep quality, especially during the COVID-19 pandemic. With this, the general objective of this study is to determine the effect of stress on the sleep quality of medical students from the University of the Philippines Manila - College of Medicine (UPCM).

METHODS

A cross-sectional study was conducted using a stratified random sample of 273 males and females of Learning Unit (LU) III (1st year) to VII (5th year) medical students from a college of medicine based in the Philippines, UPCM, during the second semester of the academic year 2021-2022. A self-administered questionnaire was distributed to assess sleep quality using the Pittsburgh Sleep Quality Index (PSQI), and stress level using the Kessler Psychological Distress Scale (K10). Kruskal-Wallis was used to test statistical differences between stress scores and the sleep quality of students from different year levels. Spearman's Rho was used to determine the correlation between stress and sleep, and a binary logistic regression was employed to study the association of stress with sleep while accounting for confounding variables namely caffeine intake, year level, daytime nap, duty hours, clinical rotation, sex, and age.

RESULTS

A high prevalence of stress (79.71%) and poor sleep quality (59.73%) among LU III to LU VII UPCM students were found, with a statistically positive correlation (⍴=0.44) 95CI [0.33-0.55] (p-value < 0.001). Both the stress scores and sleep quality indices were not statistically significantly different across LUs. Gathered data and interpreted results showed that medical students suffering from stress are more likely to have poor sleep quality, which can lead to low academic performance and high susceptibility to chronic diseases, compared to those medical students with low levels of stress. Only being an LU IV [OR=1.38 95CI (0.036-4.625)] and LU V [OR=2.13 95CI (0.296-6.936)] student had increased odds of having poor sleep quality compared to LU III students. Caffeine intake, daytime nap, duty hours, clinical rotation, sex, and age were not associated with poor sleep quality.

CONCLUSION

This study documents a statistically significant association between stress and poor sleep quality among LU III to LU VII UPCM students. A larger study covering multiple medical schools in the Philippines may be of merit for future investigations to generate nationwide data. Additional recommendations include: a) conducting a cross-sectional or a longitudinal study to detect changes in the characteristics of the population, b) observing the differences in the contributing factors at multiple points throughout the year, c) investigating the effect of dwelling set-up on sleep quality may also be investigated and d) determining if sleep quality affects the level of perceived stress of medical students.

Sleep Quality ; Students, Medical