Objective: It is important to understand the biological effects of lunar dust (regolith) if human activities, prolonged stays, and eventual habitation are to take place on the Moon. Methods: This study explains the biological effects of regolith and is based on an assessment of findings from studies that used regolith and regolith simulants and knowledge derived from the physicochemical properties of terrestrial dust. Results: In vitro cell culture studies using regolith simulants showed that the cytotoxicity and biological activity of lunar dust were generally lower than those observed for crystalline silica. Similarly, animal exposure studies that investigated the effects of regolith and regolith simulants showed limited inflammation and fibrosis, suggesting that their pulmonary toxicity is intermediate between that of titanium dioxide and crystalline silica. Although no allergy-enhancing effects, such as those seen in bronchial asthma, were observed, allergy effects have been reported for Asian dust, which has similar constituent components. This suggests that regolith could potentially enhance allergic responses. Furthermore, the results obtained using terrestrial regolith simulants may underestimate the biological effects of regolith because the simulants do not include certain materials, such as agglutinates, that are only generated in the lunar environment. Conclusions: Although the available experimental evidence does not suggest potentially severe cytotoxic, inflammatory, or fibrotic effects, careful evaluation of the chronic inhalation effects of lunar dust on future long-term lunar residents is required and this assessment should take into account its unique microstructure and surface chemical reactivity.

Objects: Male menopause, or late-onset hypogonadism (LOH) syndrome, affects the physical and mental well-being of middle-aged and older men. In Japan, awareness remains low, leading to underdiagnosis and undertreatment. This study investigated health issues, literacy, and presenteeism related to male menopause among working Japanese men, considering differences in industry and occupation. Methods: A survey was conducted among 3362 male employees aged ≥ 35 years at three companies in Tokyo representing different industries. The survey included questions on health status, aging male symptoms (AMS) scores, health literacy, workplace environment, and work impact. Presenteeism was evaluated using the single-item presenteeism question (SPQ), developed by the University of Tokyo. The survey was conducted anonymously on the company's internal server. Results: There were of valid respondents was 1,811. The respondents' demographics showed an even age distribution from 30s–60s and above. Job positions included 1.3% executives, 31.9% managers, and 79.2% staff-level employees. Awareness of "male menopause" was high (79.2%), but awareness of its specific symptoms was low (26.1%). Of the participants, 9.4% had severe AMS scores and 21.5% had moderate scores, indicating that one-quarter had moderate or higher symptoms. The most common impact on work was the inability to concentrate (58.8%). The average performance score of employees with mild or severe symptoms was 73.6%, suggesting that the prevalence of presenteeism owing to male menopausal symptoms was 26.4%. Additionally, 14.8% of the employees with symptoms reported a performance score of ≤ 50%. Conclusions: This study highlights the reality of male menopause in a large corporation and suggests that male menopause symptoms may significantly affect presenteeism.