Sex and Gender in Ageing and Longevity: Highlights From an International Course.

Gender medicine is a multidisciplinary science and represents an important perspective for pathophysiological and clinical studies in the third millennium. Here, it is provided an overview of the topics discussed in a recent course on the Role of Sex and Gender in Ageing and Longevity. The paper highlights three themes discussed in the course, i.e., the interaction of gender/sex with, i) the pathophysiology of age-related diseases; ii), the role of genetics and epigenetics in ageing and longevity and, iii) the immune responses of older people to pathogens, vaccines, autoantigens, and allergens. Although largely unexplored, it is clear that sex and gender are modulators of disease biology and treatment outcomes. It is becoming evident that men and women should no longer be considered as subgroups, but as biologically distinct groups of patients deserving consideration for specific therapeutic approaches.

Developing an intelligent prediction system for successful aging based on artificial neural networks.

Background: Due to the growing number of disabilities in elderly, Attention to this period of life is essential to be considered. Few studies focused on the physical, mental, disabilities, and disorders affecting the quality of life in elderly people. SA1 is related to various factors influencing the elderly's life. So, the objective of the current study is to build an intelligent system for SA prediction through ANN2 algorithms to investigate better all factors affecting the elderly life and promote them. Methods: This study was performed on 1156 SA and non-SA cases. We applied statistical feature reduction method to obtain the best factors predicting the SA. Two models of ANNs with 5, 10, 15, and 20 neurons in hidden layers were used for model construction. Finally, the best ANN configuration was obtained for predicting the SA using sensitivity, specificity, accuracy, and cross-entropy loss function. Results: The study showed that 25 factors correlated with SA at the statistical level of P < 0.05. Assessing all ANN structures resulted in FF-BP3 algorithm having the configuration of 25-15-1 with accuracy-train of 0.92, accuracy-test of 0.86, and accuracy-validation of 0.87 gaining the best performance over other ANN algorithms. Conclusions: Developing the CDSS for predicting SA has crucial role to effectively inform geriatrics and health care policymakers decision making.

Estimating dental age of New Zealand juveniles and subadults using Demirjian's method.

Reference data for dental age estimate is sparse in New Zealand (NZ), with only two contemporary studies. Te Moananui et al. (J For Sci. 53(2), 2008) presented modified Demirjian percentile curves to estimate dental age of Pasifika, Maori, and European males and females (n = 1383), while Timmins et al. (Forensic Sci Med Pathol. 8:101-8, 2012) found the Demirjian method (1973) was valid for a smaller sample (n = 200) of unknown ancestry. The study presented here sought to validate the Demirjian and the Te Moananui methods for a sample of the NZ population of unknown ancestry and a subgroup of known ancestry i.e., Pasifika, Maori and European, for males and females. The Demirjian method (1976) was applied to the current study's sample consisting of 3523 individuals aged 4 to < 20 years. The seven left mandibular teeth (third molar excluded) and tooth scores were summed for each individual, with the Te Moananui methods applied to this subgroup. The results revealed these methods to be less than ideal for estimating dental age of the NZ sample, for both males and females. The probit regression form of Transition Analysis (TA) was employed to calculate the mean age entering each tooth stage, for the seven teeth, to reduce age mimicry that is commonly associated with traditional regression analysis. TA results revealed Pasifika and Maori individuals to be more advanced than Caucasian individuals. The sex groups were also compared to the mean ages presented by Demirjian and Levesque with mixed results (J Dent Res. 59(7):1110-22, 1980), highlighting the need for more research in this area.

Social Mobility and Health-Related Quality of Life Trajectory Classes Among Older Women and Men.

OBJECTIVES: Changes in socioeconomic status (SES) during life may impact health in old age. We investigated whether social mobility and childhood and adulthood SES are associated with trajectories of health-related quality of life (HrQoL) over a 17-year period. METHODS: We used data from the Helsinki Birth Cohort Study (n = 2003, 46% men, mean age 61.5 years). Social mobility was derived from childhood SES, obtained from healthcare records, and register-based adulthood SES. RESULTS: Logistic regression models showed that lower adulthood SES was associated with lower physical HrQoL trajectories. Among men low (OR 3.95, p < .001), middle (OR 2.20, p = .006), and declining lifetime SES (OR 2.41, p = .001) were associated with lower physical HrQoL trajectories compared to men with high SES. Socioeconomic status was not associated with mental HrQoL trajectories. DISCUSSION: Declining SES during life course may have negative health consequences, while improving SES is potentially as beneficial as high SES to later-life health among men.

Transport digitalisation: Navigating futures of hypercognitive disablement.

People living with cognitive impairments face new forms of disablement in the context of transport digitalisation, an issue recently catalysed by controversies regarding rail ticket office closures. Transport can dramatically impact the lives of people diagnosed with dementia, who often find their mobility suddenly and dramatically impaired. Unfortunately, sociological analysis of cognitive disability has traditionally been undermined by under-theorisation. One solution can be found in classic bioethical work on hypercognitivism-the veneration of cognitive acuity-and its disabling consequences. A hypercognitive approach can nurture an attentiveness to the specificities of digital disablement. Here, disability does not emerge from digitalisation inherently, but is instead intensified by the implementation of digitalisation in line with value commitments. A more robust sociology of cognitive disability could better represent the interests of people with cognitive impairments and resist the new forms of disability that current digitalisation risks spreading.

RhoA/rho kinase pathway activation in age-associated endothelial cell dysfunction and thrombosis.

The small GTPase RhoA and the downstream Rho kinase (ROCK) regulate several cell functions and pathological processes in the vascular system that contribute to the age-dependent risk of cardiovascular disease, including endothelial dysfunction, excessive permeability, inflammation, impaired angiogenesis, abnormal vasoconstriction, decreased nitric oxide production and apoptosis. Frailty is a loss of physiological reserve and adaptive capacity with advanced age and is accompanied by a pro-inflammatory and pro-oxidative state that promotes vascular dysfunction and thrombosis. This review summarises the role of the RhoA/Rho kinase signalling pathway in endothelial dysfunction, the acquisition of the pro-thrombotic state and vascular ageing. We also discuss the possible role of RhoA/Rho kinase signalling as a promising therapeutic target for the prevention and treatment of age-related cardiovascular disease.

Leisure Attitude, Self-Rated Health, and Psychological Well-Being in Older Adults: A Moderated Mediation Model.

Purpose: A positive leisure attitude among older adults may have a beneficial effect on psychological well-being, both directly and indirectly by fostering a more positive perception of one's health. This paper presents a correlational design that explores associations among leisure attitude, self-rated health, and psychological well-being, and analyzes the potential moderating role of gender in these relationships. Patients and Methods: The sample was selected using simple random probability sampling (N= 409; 61.9% female; Mean age = 72.9; SD = 8.43¸ Range of age 53 to 93 years). Diverse sociodemographic information was collected, and leisure attitudes, self-perceived health, and psychological well-being (positive affect and emotional ties) were assessed. Results: The results revealed a positive effect of leisure attitude on self-rated health and psychological well-being, with self-rated health fully mediating the association between the behavioral component of leisure attitude and psychological well-being. Furthermore, the moderating effect of gender on the relationship between self-rated health and psychological well-being was stronger among men. Conclusion: Positive cognitive and emotional perceptions of leisure among older adults seem to benefit psychological well-being and improve self-rated health, thereby contributing to healthy ageing.

'Alright my lovely': The use of terms of endearment as a mitigation device in the care of people living with dementia in the acute hospital environment.

This paper examines how terms of endearment (ToE) are used as a mitigation device in interactions between staff and people living with dementia (PLWD) in the acute hospital environment. ToE are often discouraged in training for healthcare staff. However, this research demonstrates that they are still commonly used in practice. Using conversation analysis, video and audio data were examined to identify the interactional functions of ToE. Analysis showed that ToE play an important role in mitigating potentially face-threatening actions such as when patients are asked to repeat hard-to-interpret talk, or when patient agency is compromised through instruction sequences or having necessary healthcare tasks undertaken. The success of this mitigation is sensitive to the specific interactional circumstances, as well as the responsiveness of the HCP to the patient's voiced concerns. These findings have implications for healthcare practice, training and wider care of PLWD.

Analysis of prognostic and predictive factors in neovascular age-related macular degeneration Kuopio cohort.

PURPOSE: The aim of the study was to explore factors affecting the progression of neovascular age-related macular degeneration (nAMD) and identify predictive factors that can estimate the duration of intravitreal treatments. METHODS: This retrospective real-world study included 421 nAMD patients treated at the Kuopio University Hospital during years 2007-2021. The collected data included background demographics, treatment history, visual acuity and retinal biomarker analysis. Impact of baseline factors on age at diagnosis, treatment duration, received treatment intensity and visual acuity gains were analysed. RESULTS: Heavy smoking and high body mass index (BMI) were associated with an earlier onset, while the use of anticoagulation and anti-aggregation medication were associated with a later onset of nAMD. A low number of injections during the first year of treatment and the presence of intraretinal fluid (IRF) at baseline were associated with shorter treatment duration. Interestingly, when IRF only patients were compared to subretinal fluid (SRF) only patients, IRF patients showed higher occurrences of subretinal drusenoid deposits (43.5% vs. 15%, p = 0.04). In addition, when all patients with IRF were compared to SRF only patients, more hyperreflective foci (HRF) and complete RPE and outer retinal atrophy (cRORA; 20.7% vs. 5%, p = 0.02) were observed in patients with IRF. CONCLUSIONS: Our results reveal that heavy smoking and high BMI are accelerating factors for earlier emergence of nAMD, while the presence of IRF results in a fast-progressing disease. More intriguingly, the link between IRF and appearance of subretinal drusenoid deposits, HRF, and increased retinal atrophy was observed.

Sociocultural interactions and self-perception of health in older adults from an active participation centre: A qualitative study.

INTRODUCTION: Promoting healthy ageing is a global priority. Active Participation Centres are potentially key in fostering psychosocial and emotional health, contributing to a fulfilling and active lifestyle for older adults. AIMS: The study explores self-perceived health, perceptions of sociocultural participation, emotions that emerged when sociocultural participation, and preferences among older adults engaged in community socio-cultural activities from an Active Participation Centre. METHODS: We realised a hermeneutic study; interviews with nine older participants were conducted. Hermeneutic considerations were employed for data analysis. RESULTS: Findings reveal the centre's significance as a therapeutic space, positively influencing emotional well-being, fostering social connections, and offering diverse activity preferences. CONCLUSION: This study underscores the nuanced interplay between sociocultural engagement and self-perceived health, emphasising the need for holistic approaches to promote well-being among older adults attending Active Participation Centres.

Dimethylformamide dimethyl acetal reagent for in situ chiral analyses of organic molecules on Titan with the Dragonfly mass spectrometer space instrument (Dragonfly mission).

Thanks to the Cassini-Huygens space mission between 2004 and 2017, a lot was learned about Titan, the biggest satellite of Saturn, and its intriguing atmosphere, surface, and organic chemistry complexity. However, key questions about the potential for the atmosphere and surface chemistry to produce organic molecules of direct interest for prebiotic chemistry and life did not find an answer. Due to Titan potential as a habitable world, NASA selected the Dragonfly space mission to be launched in 2027 to Titan's surface and explore the Shangri-La surface region for minimum 3 years. One of the main goals of this mission will be to understand the past and actual abundant prebiotic chemistry on Titan, especially using the Dragonfly Mass Spectrometer (DraMS). Two recently used sample pre-treatments for Gas Chromatography - Mass Spectrometry (GC-MS mode of DraMS) analyses are planned prior analysis to extract refractory organic molecules of interest for prebiotic chemistry and astrobiology. The dimethylformamide dimethylacetal (DMF-DMA) derivatization reaction offers undoubtedly an opportunity to detect biosignatures by volatilizing refractory biological or prebiotic molecules and conserving the chiral carbons' conformation while an enantiomeric excess indicates a chemical feature induced primarily by life (and may be aided on the primitive systems by light polarization). The goal of this study is to investigate the ageing of DMF-DMA in DraMS (and likely MOMA) capsules prior to in situ analysis on Titan (or Mars). The main results highlighted by our work on DMF-DMA are first its satisfactory stability for space requirements through time (no significant degradation over a year of storage and less than 30 % of lost under thermal stress) to a wide range of temperature (0 °C to 250 °C), or the presence of water and oxidants during the derivatization reaction (between 0 and 10 % of DMF-DMA degradation). Moreover, this reagent derivatized very well amines and carboxylic acids in high or trace amounts (ppt to hundreds of ppm), conserving their molecular conformation during the heat at 145 °C for 3 min (0 to 4% in the enantiomeric form change).

The association between blood biological age at rehabilitation admission and physical activity during rehabilitation in geriatric inpatients: RESORT.

Geriatric rehabilitation inpatients have high levels of sedentary behaviour (SB) and low levels of physical activity (PA). Biological age predicted by blood biomarkers is indicative of adverse outcomes. The objective was to determine the association between blood biological age at rehabilitation admission and levels of SB and PA during rehabilitation in geriatric inpatients. Inpatients admitted to geriatric rehabilitation wards at the Royal Melbourne Hospital (Melbourne, Australia) from October 22, 2019, to March 29, 2020, in the REStORing health of acute unwell adulTs (RESORT) observational cohort were included. Blood biological age was predicted using SenoClock-BloodAge, a hematological ageing clock. Patients wore an inertial sensor to measure SB and PA. Logistic regression analyses were conducted. A total of 111 patients (57.7% female) with mean age 83.3 ± 7.5 years were included in the analysis. The mean blood biological age was 82.7 ± 8.4 years. Patients with 1-year higher blood biological age had higher odds of having high SB measured as non-upright time greater than 23 h/day (odds ratio (OR): 1.050, 95% confidence interval (CI): 1.000-1.102). Individuals having 1-year higher age deviation trended towards lower odds of having high levels of PA measured as stepping time greater than 7.4 min/day (OR: 0.916, CI: 0.836-1.005) and as greater than 19.5 sit-to-stand transitions/day (OR: 0.915, CI: 0.836-1.002). In conclusion, higher biological age was associated with higher levels of SB and trended towards lower PA. Incorporating blood biological age could facilitate resource allocation and the development of more tailored rehabilitation plans.

Epigenetic age estimation of wild mice using faecal samples.

Age is a key parameter in population ecology, with a myriad of biological processes changing with age as organisms develop in early life then later senesce. As age is often hard to accurately measure with non-lethal methods, epigenetic methods of age estimation (epigenetic clocks) have become a popular tool in animal ecology and are often developed or calibrated using captive animals of known age. However, studies typically rely on invasive blood or tissue samples, which limit their application in more sensitive or elusive species. Moreover, few studies have directly assessed how methylation patterns and epigenetic age estimates compare across environmental contexts (e.g. captive or laboratory-based vs. wild animals). Here, we built a targeted epigenetic clock from laboratory house mice (strain C57BL/6, Mus musculus) using DNA from non-invasive faecal samples, and then used it to estimate age in a population of wild mice (Mus musculus domesticus) of unknown age. This laboratory mouse-derived epigenetic clock accurately predicted adult wild mice to be older than juveniles and showed that wild mice typically increased in epigenetic age over time, but with wide variation in epigenetic ageing rate among individuals. Our results also suggested that, for a given body mass, wild mice had higher methylation across targeted CpG sites than laboratory mice (and consistently higher epigenetic age estimates as a result), even among the smallest, juvenile mice. This suggests wild and laboratory mice may display different CpG methylation levels from very early in life and indicates caution is needed when developing epigenetic clocks on laboratory animals and applying them in the wild.

Contacting the gut: Mitochondria-associated Endoplasmic Reticulum Membranes in the Enteric Nervous System.

Changes in the connections between the endoplasmic reticulum (ER) and mitochondria, as well as alterations in mitochondria-associated ER membrane (MAM) signalling, have been documented in various neurodegenerative diseases affecting the brain. Despite the growing recognition of the significance of the gut-brain axis in neurodegenerative conditions, there has been no prior investigation into the biology of MAM within the enteric nervous system (ENS). Our recent research reveals, for the first time, the existence of connections between the ER and mitochondria within enteric neurons. Additionally, we observed alterations in the dynamics of these connections in the enteric neurons from a mouse model exhibiting age-related neurodegeneration. These findings provide the first detailed characterization of MAM in the ENS under physiological conditions and in a mouse model of age-associated neurodegeneration and shed new light on the potential role of enteric MAM in the context of neurodegenerative disorders.

Sexual health among the oldest old: a population-based study among people aged 85 years and older in Stockholm, Sweden.

Background: Sexual health is an important contributor to the well-being and life satisfaction of people aged ≥85 years, known as the oldest old. However, little is known about sexual health in this population. Aim: To examine aspects of sexual health among the oldest old and explore its associations with sociodemographic, health-related, and lifestyle factors. Methods: We conducted a population-based cross-sectional study including 183 individuals aged ≥85 years who were residents in Stockholm County, Sweden. Responders (response rate, 63%) were interviewed on a range of health, sociodemographic, and lifestyle parameters, including aspects of sexual health. Participants' responses to the sexual health items were reported as proportions with 95% CIs. Associations were examined with multivariable logistic regression. Outcomes: We examined sexual activity, sexual satisfaction, problems related to sexual health, and inquiries on sexual health by a health care provider. Results: Twelve percent of participants (95% CI, 8%-17.6%) were sexually active, and 63.9% (95% CI, 56.5%-70.9%) were satisfied with their sexual lives during the past year. A third (35%; 95% CI, 28.4%-42.2%) reported at least a problem related to sexual health. Only 2.2% (95% CI, 0.6%-5.5%) were asked about sexual health by a health care provider, while 8.2% (95% CI, 4.7%-13.2%) identified a need for such an assessment. Yet, 85.2% (95% CI, 79.3%-90.0%) indicated no need for their sexual health to be evaluated by a health care provider. Being partnered was positively associated with sexual activity (adjusted odds ratio, 9.13; 95% CI, 2.53-32.90), whereas having strong social support was positively associated with being satisfied with one's sexual life (adjusted odds ratio, 2.96; 95% CI, 1.53-5.74). Clinical Implications: Health care providers should be proactive in assessing the sexual health of the oldest individuals. Strengths and Limitations: A representative sample of an underresearched population was used in this study. However, the generalizability of our findings may be restricted due to the small sample. To maintain statistical power from a relatively small sample, we might have lost explanatory power. Given the observational cross-sectional nature of the data, we cannot draw causal inferences based on the observed associations. Conclusions: A 10th of participants were sexually active, and the majority were satisfied with their sexual lives. Although many participants reported problems related to sexual health, few expressed the need to discuss sexual health with health care providers. Future studies should explore potential barriers to addressing sexual health and unmet health care needs among the oldest old.

Characterisation of behaviours relevant to apathy syndrome in the aged male rat.

Apathy is a complex psychiatric syndrome characterised by motivational deficit, emotional blunting and cognitive changes. It occurs alongside a broad range of neurological disorders, but also occurs in otherwise healthy ageing. Despite its clinical prevalence, apathy does not yet have a designated treatment strategy. Generation of a translational animal model of apathy syndrome would facilitate the development of novel treatments. Given the multidimensional nature of apathy, a model cannot be achieved with a single behavioural test. Using a battery of behavioural tests we investigated whether aged rats exhibit behavioural deficits across different domains relevant to apathy. Using the effort for reward and progressive ratio tasks we found that aged male rats (21-27 months) show intact reward motivation. Using the novelty supressed feeding test and position-based object exploration we found aged rats showed increased anxiety-like behaviour inconsistent with emotional blunting. The sucrose preference test and reward learning assay showed intact reward sensitivity and reward-related cognition in aged rats. However, using a bowl-digging version of the probabilistic reversal learning task, we found a deficit in cognitive flexibility in aged rats that did not translate across to a touchscreen version of the task. While these data reveal important changes in cognitive flexibility and anxiety associated with ageing, aged rats do not show deficits across other behavioural domains relevant to apathy. This suggests that aged rats are not a suitable model for age-related apathy syndrome. These findings contrast with previous work in mice, revealing important species differences in behaviours relevant to apathy syndrome in ageing.

The association between cannabis use and neuroimaging measures in older adults: findings from the UK biobank.

BACKGROUND: Cannabis use has increased in recent years. However, the long-term implications of cannabis use on brain health remain unknown. We explored the associations of cannabis use with volumetric brain magnetic resonance imaging (MRI) measures in dementia-free older adults. METHODS: This cross-sectional and longitudinal study included dementia-free participants of the UK Biobank aged ≥60 years. Linear regression models were used to evaluate the association of cannabis use and patterns of use with volumetric brain MRI measures. The association between cannabis use and change in brain MRI measures over time was also tested. All models were adjusted for potential confounders. RESULTS: The sample included 19,932 participants (mean age 68 ± 5 years, 48% men), 3,800 (19%) reported lifetime use of cannabis. Cannabis use was associated with smaller total, white, grey and peripheral cortical grey matter volumes (B = -6,690 ± 1,157; P < 0.001, B = -4,396 ± 766; P < 0.001, B = -2,140 ± 690; P = 0.002 and B = -2,451 ± 606; P < 0.001, respectively). Among cannabis users, longer duration of use was associated with smaller total brain, grey and cortical grey matter volumes (B = -7,878 ± 2,396; P = 0.001, B = -5,411 ± 1,430; P < 0.001, B = -5,396 ± 1,254; P < 0.001, respectively), and with increased white matter hyperintensity volume (B = 0.09 ± 0.03; P = 0.008). Additionally, current vs. former users (B = -10,432 ± 4,395; P = 0.020) and frequent versus non-frequent users (B = -2,274 ± 1,125; P = 0.043) had smaller grey and cortical grey matter volumes, respectively. No significant associations were observed between cannabis use and change in brain MRI measures. DISCUSSION: Our findings suggest that cannabis use, particularly longer duration and frequent use, may be related to smaller grey and white matter volumes in older ages, but not to late-life changes in these measures over time.

Narrative Review on the Use of Cladribine Tablets as Exit Therapy for Stable Elderly Patients with Multiple Sclerosis.

The number of ageing people with relapsing multiple sclerosis (RMS) is increasing. The efficacy of disease-modifying therapies (DMTs) for RMS declines with age. Also, older persons with MS may be more susceptible to infections, hospitalisations and malignancy. Aging people with MS have higher rates of comorbidities versus aged-matched controls, increasing the individual risk of disability. We review the therapeutic properties of cladribine tablets (CladT) in ageing people with RMS, with regard to their utility for allowing these individuals to cease continuous administration of a DMT (i.e. to act as an "exit therapy"). CladT is thought to be an immune reconstitution therapy, in that two short courses of oral treatment 1 year apart provide suppression of MS disease activity in responders that far outlasts the duration of treatment and post-treatment reductions in lymphocyte counts. Post hoc analyses, long-term follow-up of populations with RMS in randomised trials, and real-world evidence suggest that the efficacy of CladT is probably independent of age, although more data in the elderly are still needed. No clear adverse signals for lymphopenia or other adverse safety signals have emerged with increasing age, although immunosenescence in the setting of age-related "inflammaging" may predispose elderly patients to a higher risk of infections. Updating vaccination status is recommended, especially against pneumococci and herpes zoster for older patients, to minimise the risk of these infections. CladT may be a useful alternative treatment for ageing people with MS who often bear a burden of multiple comorbidities and polypharmacy and who are more exposed to the adverse effects of continuous immunosuppressive therapy.

Influence of age and sex on longitudinal metabolic profiles and body weight trajectories in the UK Biobank.

BACKGROUND: Accurate characterization of how age influences body weight and metabolism at different stages of life is important for understanding ageing processes. Here, we explore observational longitudinal associations between metabolic health and weight from the fifth to the seventh decade of life, using carefully adjusted statistical designs. METHODS: Body measures and biochemical data from blood and urine (220 measures) across two visits were available from 10 104 UK Biobank participants. Participants were divided into stable (within ±4% per decade), weight loss and weight gain categories. Final subgroups were metabolically matched at baseline (48% women, follow-up 4.3 years, ages 41-70; n = 3368 per subgroup) and further stratified by the median age of 59.3 years and sex. RESULTS: Pulse pressure, haemoglobin A1c and cystatin-C tracked ageing consistently (P < 0.0001). In women under 59, age-associated increases in citrate, pyruvate, alkaline phosphatase and calcium were observed along with adverse changes across lipoprotein measures, fatty acid species and liver enzymes (P < 0.0001). Principal component analysis revealed a qualitative sex difference in the temporal relationship between body weight and metabolism: weight loss was not associated with systemic metabolic improvement in women, whereas both age strata converged consistently towards beneficial (weight loss) or adverse (weight gain) phenotypes in men. CONCLUSIONS: We report longitudinal ageing trends for 220 metabolic measures in absolute concentrations, many of which have not been described for older individuals before. Our results also revealed a fundamental dynamic sex divergence that we speculate is caused by menopause-driven metabolic deterioration in women.

Radon deficit technique applied to the study of the ageing of a spilled LNAPL in a shallow aquifer.

A recent diesel spill (dated January 2019 ± 1 month) in a refilling station is investigated by the Radon deficit technique. The primary focus was on quantifying the LNAPL pore saturation as a function of duration of ageing, and on proposing a predictive model for on-site natural attenuation. A biennial monitoring of the local fluctuating shallow aquifer has involved the saturated zone nine times, and the vadose zone only once. Rn background generally measured in external and upstream wells is elaborated further due to the site characteristics, using drilling logs and phreatic oscillations. Notably, this study marks the first application of the Rn deficit method to produce a detailed Rn background mapping throughout the soil depth. Simultaneously, tests are performed on LNAPL surnatant samples to study diesel ageing. In particular, they are focused on temporal variations of LNAPL viscosity (from an initial 3.90 cP to 8.99 cP, measured at 25 °C, after 34 months), and Rn partition coefficient between the pollutant and water (from 47.7 to 80.2, measured at 25 °C, after 14 months). Rn diffusion is also measured in different fluids (0.092 cm2 s-1, 1.14 × 10-5 cm2 s-1, and 2.53 × 10-6 cm2 s-1 at 25 °C for air, water and LNAPL, respectively) directly. All parameters and equations utilized during this study are introduced, discussing their influence on Radon deficit technique from a theoretical point of view. Experimental findings are used to mitigate the effect of LNAPL ageing and of phreatic oscillations on determination of LNAPL saturation index (S.I.LNAPL). Finally, S.I.LNAPL dataset is discussed and elaborated to show the pollutant attenuation across subsurface over time, induced by natural processes primarily. The proposed predictive model for on-site natural attenuation suggests a half-removal time of one year and six months. The significance of such models lies in their capability to assess site-specific reactions to pollutants, thereby enhancing the effectiveness of remediation efforts over time. These experimental findings may offer a novel approach to application of Rn deficit technique and to environmental remediation of persistent organic compounds.