Po-Wen Ku

Background: This study assessed whether higher levels of fine particulate matter (PM _2.5 ) reduce the protective effects of leisure-time physical activity (LTPA) on all-cause, cardiovascular, and cancer mortality, and explored the PM _2.5 threshold beyond which attenuation occurs. Methods: We conducted two complementary investigations. First, a systematic review and meta-analysis (per PRISMA guidelines) identified eligible cohort studies from PubMed, Web of Science, Embase, and SPORTDiscus (from inception to 6 January 2025) that examined the independent or joint associations of LTPA and PM₂.₅ with mortality among adults (≥ 18 years). Second, an individual-level pooled analysis using harmonized data from three cohorts was performed using Cox regression modeling to assess the associations observed in the meta-analysis. Results: In Study One, a total of seven cohort studies ( n = 1,515,094; deaths = 115,196) were included in the meta-analysis, revealing that the reduction in all-cause mortality risk diminished with higher PM _2.5 exposure. Meeting the recommended LTPA level (7.5–15 MET-h/week) reduced all-cause mortality risk by approximately 30% at PM _2.5 < 25 μg/m ³ but only 12–15% at 25 + μg/m ³ . Study Two (three cohorts; n = 869,038; deaths = 45,080) confirmed this pattern. Individuals meeting the recommended LTPA level (7.5–15 MET-h/week) had a lower risk of all-cause mortality compared to those in the highest-risk group (reference: < 1 MET-h/week and PM _2.5 : 35–50 μg/m ³ ). Hazard ratios (HRs) varied by PM _2.5 exposure, with lower HRs indicating a greater protective effect: 35–50 μg/m ³ (HR = 0.75, 95% CI: 0.61–0.93), 25–35 μg/m ³ (HR = 0.67, 95% CI: 0.57–0.79), 15–25 μg/m ³ (HR = 0.34, 95% CI: 0.29–0.39), 10–15 μg/m ³ (HR = 0.34, 95% CI: 0.28–0.41), and < 10 μg/m ³ (HR = 0.30, 95% CI: 0.25–0.37). Higher levels of LTPA were generally associated with lower all-cause and cause-specific mortality across most PM₂.₅ exposure categories, but the protective effects were attenuated at PM₂.₅ levels 25 + μg/m ³ for all outcomes and became non-significant for cancer mortality at 35–50 μg/m ³ . Conclusions: LTPA is beneficial for all-cause, cardiovascular, and cancer mortality even at relatively high PM _2.5 levels, with greater benefits observed under cleaner air conditions. However, its protective effects are attenuated at 25 + μg/m ³ for all outcomes and become less evident at 35–50 μg/m ³ , particularly for cancer mortality. PROSPERO Registration Number: CRD42023395364.

Sleep disturbances are commonly reported in working populations. While research has identified various work-related risk factors for poor sleep, the relationship between prior occupational physical activity (OPA) and future sleep disturbances remains unclear. The study aimed to examine the prospective associations between OPA levels and sleep disturbances in adults. We utilized longitudinal data from the MJ cohort study (1998 to 2022). The sample (N = 62528) consisted of adults aged 18 years or above. The mean age (in years) was 35.9 (SD = 9.5), and they were working full-time and reported no sleep disturbances at baseline. We examined the prospective associations between self-reported OPA levels (light, moderate, moderately heavy, and heavy) at baseline, and the presence of sleep disturbances at a mean follow-up time of 5.6 years (SD = 4.5). Cox proportional hazard models were conducted, adjusting for potential confounding variables. Using light OPA level as the reference group, individuals with moderately heavy OPA (HR: 1.13, 95% CI: 1.07, 1.19, p < 0.001) and heavy OPA (HR: 1.22, 95% CI: 1.11, 1.34, p < 0.001) at baseline had a higher risk of sleep disturbances at follow-up. Stratified analyses showed that the association between higher levels of OPA and sleep disturbances remained across different subgroups. Notably, these associations were more pronounced among females (p_interaction = 0.008), for moderately heavy OPA (HR: 1.23, 95% CI: 1.12, 1.35, p < 0.001) and heavy OPA (HR: 1.45, 95% CI: 1.10, 1.91, p = 0.009). These associations were also more pronounced in certain occupational groups (p_interaction = 0.003), where only heavy OPA was significantly associated with an elevated risk of sleep disturbances among civil servants (HR: 1.66, 95% CI: 1.08, 2.55, p = 0.020) and office workers, professionals and technicians (HR: 1.49, 95% CI: 1.09, 2.05, p = 0.010). Higher OPA levels were associated with an increased risk of sleep disturbances. Workplace support or interventions are in need to improve sleep patterns.

What is Known on the Subject?: People living with schizophrenia have reduced physical function and are more likely to experience loneliness than those without condition. Low physical function is associated with greater loneliness in people with psychosis. However, it is unclear whether social isolation and loneliness contribute to impaired physical function in this population. Loneliness is linked to an increased risk of physical function impairment among older individuals, but research on patients living with schizophrenia is limited. What This Paper Adds to Existing Knowledge?: This study is the first to evaluate the longitudinal association of social isolation and loneliness with physical function among inpatients living with schizophrenia. It showed that more than one third of the participants experienced a decline in physical function over a 2‐year period. Loneliness, rather than social isolation, was associated with an increase in physical function impairment over 2 years among inpatients living with schizophrenia. What are the Implications for Practice?: Healthcare professionals should recognize loneliness as a potential risk factor for impaired physical function among inpatients diagnosed with schizophrenia. It is recommended that people living with schizophrenia are assessed for loneliness and that interventions are offered to alleviate their feelings of loneliness. Implementing interventions to reduce loneliness may help improve physical function and overall quality of life for individuals living with schizophrenia. Introduction: Patients living with schizophrenia often experience low physical function, which is associated with negative health outcomes. Therefore, investigating the risk factors for physical function is crucial in this population.Aim: This study examined the longitudinal association of social isolation and loneliness with physical function among inpatients living with schizophrenia.Methods: Physical function was assessed using measures of activities daily living (ADL), instrumental activities daily living (IADL) and the combination scores of ADL/IADL. Social isolation was indexed with five types of social connection and loneliness was measured using UCLA Loneliness Scale.Results: Social isolation was not associated with the measures of physical function over 2 years. Loneliness exhibited an association with IADL and ADL/IADL at follow‐up, after adjustment for baseline levels of the outcomes. These associations remained when both social isolation and loneliness were simultaneously entered into the model.Discussion: Loneliness, rather than social isolation, was associated with increased physical function impairment over 2 years among inpatients living with schizophrenia.Implications for Practice: Healthcare professionals should consider loneliness as a potential risk factor for impaired physical function. It would be beneficial to assess patients for loneliness and implement interventions to reduce feelings of loneliness.

Background: Walking is the fundamental component of taking steps and is the main form of physical activity among individuals with schizophrenia; it also offers a range of health benefits. This study aimed to examine the associations between daily steps and cognitive function and further explored how many steps were related to better cognitive function among inpatients with schizophrenia. Methods: Inpatients with schizophrenia were recruited from long-stay psychiatric wards across two hospitals (n=199 at site 1 and n=195 at site 2). Daily steps were collected with an accelerometer for 7 days. Four cognitive domains (attention, processing speed, reaction time, and motor speed) were tested at site 1, and two cognitive domains (attention and processing speed) were tested at site 2. The associations of daily steps and levels of steps/day with cognitive function were tested using multivariable linear regressions separated by site. Covariates included demographic variables, weight status, metabolic parameters, and clinical state. Results: Participants took an average of 7445 (±3442) steps/day. More steps were related to better attention, processing speed, reaction time, and motor speed after multivariable adjustments. Compared with participants taking <5000 steps/day, those taking ≥5000 steps/day showed significantly better processing speed. Participants taking ≥7500 steps/day were associated with better attention, better reaction time, and better motor speed than those taking <5000 steps/day. Conclusion: Daily steps are associated with better cognitive function among inpatients with schizophrenia. The optimal benefit for cognitive function among this clinical population is achieving 7500 steps/day or more.