Dehydration and cognition: an understated relation

Food and Water Insecurity and Functional Disability in Adults

Importance

Evidence from diverse global populations suggests that household food insecurity (HFI) is associated with adult disability, but the association between household water insecurity (HWI) and disability remains understudied. Examinations of the joint association of dual HFI and HWI with disability are lacking.

Objective

To explore independent and joint associations of HFI and HWI with functional disability in Ecuadorian adults.

Design, Setting, and Participants

This cross-sectional study used data from the 2018 Ecuadorian National Health and Nutrition Survey, a nationally representative, population-based survey conducted in Ecuador. The study included adults (aged 18-99 years) with information on sociodemographic characteristics, household food and water security, and functional disability status. Data were collected in 2 waves of the survey, from November 2018 to January 2019 and June to July 2019. Statistical analysis was performed from May to December 2024.

Exposures

HFI, WFI, or both.

Main outcomes and Measures

The primary outcome was self-reported functional disability, assessed using the Washington Group Short Set on Functioning, a tool that uses a set of 6 questions to measure activity limitations.

Results

Among 42 071 participants (mean [SE] age, 48.0 [0.1] years; 31 683 male [75.3%]; 1840 African descendant [4.4%], 5184 Indigenous [12.3%], and 35 047 Mestizo ethnic majority group [83.3%]), most lived in urban areas (26 164 participants [62.2%]). Exposure to HFI only was associated with an increased risk for any functional disability (adjusted relative risk [aRR], 1.44; 95% CI, 1.37-1.52), as well as sensory (aRR, 1.43; 95% CI, 1.35-1.52), physical (aRR, 1.56, 95% CI, 1.42-1.72), and cognitive (aRR, 1.78; 95% CI, 1.61-1.98) disabilities. HWI exposure only was associated with increased risk for any functional disability (aRR, 1.12; 95% CI, 1.06-1.20), as well as sensory (aRR, 1.17; 95% CI, 1.09-1.25), physical (aRR, 1.15; 95% CI, 1.05-1.26), and cognitive (aRR, 1.17; 95% CI, 1.03-1.34) disabilities. Exposure to dual HFI and HWI was associated with a greater increase in risk than HFI or HWI alone of any functional disability (aRR, 1.61; 95% CI, 1.50-1.72), as well as sensory (aRR, 1.65; 95% CI, 1.52-1.79), physical (aRR, 1.72; 95% CI, 1.59-1.87), and cognitive (aRR, 2.01; 95% CI, 1.76-2.29) disabilities.

Conclusion and Relevance

In this study, dual exposure to HFI and HWI was associated with a greater increase in risk of any and specific functional disabilities compared with independent contributions of HFI and HWI alone. These findings highlight the importance of addressing HFI and HWI jointly rather than independently when conducting research on disability and other health outcomes and in designing policies and programs to protect at-risk adults and their households.

The cumulative effects of consecutive days of prolonged, physical work or activity on heat strain and physical performance: a systematic review

With climate warming, there is an urgent need to understand the health effects of occupational heat exposure. This systematic review examined the cumulative effects of consecutive days of prolonged physical work or activity on heat strain and physical performance. Electronic databases MEDLINE, SPORTDiscus, PsychInfo, and Academic Search Complete were searched until July 2024 with terms related to work, consecutive days, and heat. Studies were included if they involved ≥4 h of physical work/activity on ≥2 consecutive days, and included a measure of heat strain (e.g., core temperature) or physical performance (e.g., repetitions). After removing duplicates, 6030 studies were screened (title and abstract), 133 progressed to full-text screening, and 33 met the inclusion criteria with risk of bias assessed. However, only five studies used standardized environmental and work conditions across days. Synthesis of the cumulative effects (without meta-analysis) was therefore restricted to these studies. None observed a cumulative impact on heat strain, as indexed by a higher core temperature or heart rate compared to day 1. None reported a reduction in physical task performance across days. These findings indicate that the cumulative effects of occupational heat exposure on heat strain and physical task performance were minimal, although evidence supporting this conclusion is sparse. PROSPERO registration: CRD42023452936.

Kenyan school book knowledge for water, sanitation, hygiene and health education interventions: Disconnect, integration or opportunities?

BACKGROUND

Schools, depending on their access to and quality of water, sanitation and hygiene (WASH) and the implementation of healthy behaviours, can be critical for the control and spread of many infectious diseases, including COVID-19. Schools provide opportunities for pupils to learn about the importance of hygiene and WASH-related practice, and build healthy habits and skills, with beneficial medium- and long-term consequences particularly in low- and middle-income countries: reducing pupils' absenteeism due to diseases, promoting physical, mental and social health, and improving learning outcomes. WASH services alone are often not sufficient and need to be combined with educational programmes. As pupils disseminate their acquired health-promoting knowledge to their (extended) families, improved WASH provisions and education in schools have beneficial effects also on the community. International organisations frequently roll out interventions in schools to improve WASH services and, in some cases, train pupils and teachers on safe WASH behaviours. How such interventions relate to local school education on WASH, health promotion and disease prevention knowledge, whether and how such knowledge and school books are integrated into WASH education interventions in schools, are knowledge gaps we fill.

METHODS

We analyzed how Kenyan primary school science text book content supports WASH and health education by a book review including books used from class 1 through class 8, covering the age range from 6 to 13 years. We then conducted a rapid literature review of combined WASH interventions that included a behaviour change or educational component, and a rapid review of international policy guidance documents to contextualise the results and understand the relevance of books and school education for WASH interventions implemented by international organisations. We conducted a content analysis based on five identified thematic categories, including drinking water, sanitation, hygiene, environmental hygiene & health promotion and disease risks, and mapped over time the knowledge about WASH and disease prevention.

RESULTS

The books comprehensively address drinking water issues, including sources, quality, treatment, safe storage and water conservation; risks and transmission pathways of various waterborne (Cholera, Typhoid fever), water-based (Bilharzia), vector-related (Malaria) and other communicable diseases (Tuberculosis); and the importance of environmental hygiene and health promotion. The content is broadly in line with internationally recommended WASH topics and learning objectives. Gaps remain on personal hygiene and handwashing, including menstrual hygiene, sanitation education, and related health risks and disease exposures. The depth of content varies greatly over time and across the different classes. Such locally available education materials already used in schools were considered by none of the WASH education interventions in the considered intervention studies.

CONCLUSIONS

The thematic gaps/under-representations in books that we identified, namely sanitation, hygiene and menstrual hygiene education, are all high on the international WASH agenda, and need to be filled especially now, in the context of the current COVID-19 pandemic. Disconnects exist between school book knowledge and WASH education interventions, between policy and implementation, and between theory and practice, revealing missed opportunities for effective and sustainable behaviour change, and underlining the need for better integration. Considering existing local educational materials and knowledge may facilitate the buy-in and involvement of teachers and school managers in strengthening education and implementing improvements. We suggest opportunities for future research, behaviour change interventions and decision-making to improve WASH in schools.

Effects of the Amount and Frequency of Fluid Intake on Cognitive Performance and Mood among Young Adults in Baoding, Hebei, China: A Randomized Controlled Trial

Water is a critical nutrient that is important for the maintenance of the physiological function of the human body. This article aimed to investigate the effects of the amount and frequency of fluid intake on cognitive performance and mood. A double-blinded randomized controlled trial was designed and implemented on college students aged 18–23 years in Baoding, China. Participants were randomly assigned into one of three groups: the recommended behavior group (RB group) who drank 200 mL of water every 2 h, the half amount group (HA group) who drank 100 mL of water every 2 h, and the high frequency group (HF group) who drank 110 mL of water every 1 h. The intervention lasted 2 days. Urine osmolality, cognitive performance, and mood of participants in each group were compared using the one-way analysis of variance (ANOVA). A total of 92 participants (46 females, 46 males) completed this study with a completion rate of 95.8%. The urine osmolality of the HA group was higher than that of the RB group and the HF group at two time points (p < 0.05). At time point 1, the scores in the portrait memory test and vigor were statistically different (F = 20.45, p < 0.001; F = 5.46, p = 0.006). It was found that the scores for the portrait memory test in the RB group were lower than those in the HA group and the HF group (p = 0.007; p < 0.001), while the scores of the HF group were higher than those of the HA group (p < 0.001). The scores for vigor in the RB group were significantly higher than those of the HA group (p = 0.006), and they were also significantly higher than those of the HF group (p = 0.004). At time point 2, only the scores for vigor were statistically different (F = 3.80, p = 0.026). It was found that the scores for vigor in the RB group were higher than those in the HA group and HF group (p = 0.018; p = 0.019). Both the amount and frequency of fluid intake may affect urine osmolality and vigor, but these factors have limited impacts on cognitive performance. Rational fluid intake behavior may be beneficial to improve the hydration status and mood of young adults. More research is needed, especially experimental research, to allow causal conclusions to be drawn.

Non Invasive Skin Hydration Level Detection Using Machine Learning

Dehydration and overhydration can help to improve medical implications on health. Therefore, it is vital to track the hydration level (HL) specifically in children, the elderly and patients with underlying medical conditions such as diabetes. Most of the current approaches to estimate the hydration level are not sufficient and require more in-depth research. Therefore, in this paper, we used the non-invasive wearable sensor for collecting the skin conductance data and employed different machine learning algorithms based on feature engineering to predict the hydration level of the human body in different body postures. The comparative experimental results demonstrated that the random forest with an accuracy of 91.3% achieved better performance as compared to other machine learning algorithms to predict the hydration state of human body. This study paves a way for further investigation in non-invasive proactive skin hydration detection which can help in the diagnosis of serious health conditions.