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Fulltext Assessment of heat stress contributing factors in the indoor environment among vulnerable populations in Klang Valley using principal component analysis (PCA)

Muhamad SN, How V, Lim FL, Md Akim A, Karuppiah K, Mohd Shabri NSA

Sci Rep, 2024 Jul 15;14(1):16265.
PMID: 39009671 DOI: 10.1038/s41598-024-67110-w

Rising global temperatures can lead to heat waves, which in turn can pose health risks to the community. However, a notable gap remains in highlighting the primary contributing factors that amplify heat-health risk among vulnerable populations. This study aims to evaluate the precedence of heat stress contributing factors in urban and rural vulnerable populations living in hot and humid tropical regions. A comparative cross-sectional study was conducted, involving 108 respondents from urban and rural areas in Klang Valley, Malaysia, using a face-to-face interview and a validated questionnaire. Data was analyzed using the principal component analysis, categorizing factors into exposure, sensitivity, and adaptive capacity indicators. In urban areas, five principal components (PCs) explained 64.3% of variability, with primary factors being sensitivity (health morbidity, medicine intake, increased age), adaptive capacity (outdoor occupation type, lack of ceiling, longer residency duration), and exposure (lower ceiling height, increased building age). In rural, five PCs explained 71.5% of variability, with primary factors being exposure (lack of ceiling, high thermal conductivity roof material, increased building age, shorter residency duration), sensitivity (health morbidity, medicine intake, increased age), and adaptive capacity (female, non-smoking, higher BMI). The order of heat-health vulnerability indicators was sensitivity > adaptive capacity > exposure for urban areas, and exposure > sensitivity > adaptive capacity for rural areas. This study demonstrated a different pattern of leading contributors to heat stress between urban and rural vulnerable populations.
Association between physiological responses and heat shock protein 70 (HSP70) expressions in the vulnerable populations of Kuala Lumpur

Muhamad SN, Lim FL, Md Akim A, Karuppiah K, Mohd Shabri NSA, How V

Int J Environ Health Res, 2024 Apr 14.
PMID: 38616509 DOI: 10.1080/09603123.2024.2340125

Continued heat exposure can cause physiological and cellular responses. This study investigated the association between physiological responses and heat shock protein 70 (HSP70) expressions in Kuala Lumpur's urban vulnerable population. We conducted a cross-sectional study involving 54 participants from four areas classified as experiencing moderate to strong heat stress. Physiological measurements included core body temperature, heart rate, and diastolic and systolic blood pressure. RT-qPCR and ELISA were also performed on blood samples to assess HSP70 gene and protein expressions. Despite indoor heat stress, participants maintained normal physiological parameters while there were significant indications of HSP70 expression at both the gene and protein levels. However, our study found no significant correlation (p > 0.05) between physiological responses and HSP70 expressions. This study shows no interaction between physiological responses and HSP70 expressions in the study population, revealing the complex mechanisms of indoor heat stress in vulnerable individuals.
Fulltext Two new xanthones from Calophyllum nodusum (Guttiferae)

Nasir NM, Rahmani M, Shaari K, Ee GC, Go R, Kassim NK, et al.

Molecules, 2011 Oct 25;16(11):8973-80.
PMID: 22027953 DOI: 10.3390/molecules16118973

The air-dried powdered stem bark of Calophyllum nodusum (Guttiferea) collected from Sandakan (Sabah, Malaysia), was extracted sequentially with hexane, chloroform and methanol. The solvents were removed by rotary evaporator to give dark viscous extracts. Detailed and repeated chromatographic separation of the extracts lead to isolation of two new xanthones, identified as nodusuxanthone and trapezifolixanthone A. Other common terpenoids such as betulinic acid, lupeol, stigmasterol and friedelin were also isolated from the extracts and identified. The structures of the compounds were established by detailed spectral analysis and comparison with previously reported data.
Adapting to heat-health vulnerability in temperate climates: current adaptation and mitigation responses and future predictions in Aotearoa New Zealand

Muhamad SN, Mohd Shabri NSA, Cotter JD, Bolton A, How V, Lim FL, et al.

Rev Environ Health, 2024 Nov 21.
PMID: 39562285 DOI: 10.1515/reveh-2024-0101

INTRODUCTION: Climate change is raising global temperatures, leading to more extreme heat events, even in temperate climates like Aotearoa|New Zealand (A|NZ). The impact of rising temperatures and the adequacy of planning measures remain underexplored. This paper highlights A|NZ's anticipated heat-health challenges by analyzing vulnerable populations and assessing current response systems, thereby reinforcing the need for system-level redress, mitigation and adaptation.
CONTENT: A scoping review examined the impact of heat and existing mitigation and adaptation responses for vulnerable populations in temperate regions, with a focus on A|NZ. Additionally, temperature trend analysis was conducted for current and projected trends using Climate CHIP for six major heat-affected cities in A|NZ to assess the recognition of heat as a societal concern.
SUMMARY AND OUTLOOK: The review identified mitigation and adaptation strategies for existing vulnerable groups and discovered other potential vulnerable groups in A|NZ, including Indigenous people (Māori), Pacific communities, low-income groups, migrants, and visitors. Temperature trends show an increasing pattern, suggesting heightened future heat-related impacts on these populations. This review reveals A|NZ's growing vulnerability to rising temperatures, particularly among high-risk groups, and calls for stronger mitigation and adaptation strategies to address future heat-health risks.