Background: Although conflicting findings abound, gender-related differences in olfactory identification have received continuous attention. To our best knowledge, no systematic and quantitative research has examined gender differences in olfaction identification at various stages of life. The present study aimed to find out if there is gender difference in human olfaction identification in different life stages. Methodology: Studies cited in the PubMed database were searched from its inception to August 2017 using the terms "olfact*" or "smell" and "gender" or "sex". The effect size of each comparison was calculated. 24 studies were included in this meta-analysis. Results: In this meta-analysis, we used Cohen's d to determine the effects sizes for the comparisons between women versus men among different groups. Its value was 0.18 (95% CI:-0.13 to 0.49) in Group A (age<18years), 0.62 (95% CI: 0.43 to 0.81) in Group B (age 18-50years), and 0.33 (95% CI:-0.01 to 0.66) in Group C. The effect was considered relatively small in Group A (age<18years) and Group C (age>50years), and a medium effect in Group B (age18-50 years). Moreover, a significant difference was only present in Group B (age18-50 years). Summarizing, the gender effect was only present in the group aged 18-50 years, in which women outperformed men significantly in odor identification. Conclusions: This meta-analytic review indicated that the gender differences only exist in young adults (age18-50 years), while absent in juveniles (age<18years) or an aged cohort (age >50years). Females outperformed males in the young adults.

BACKGROUND: Although ageing and neurodegenerative diseases, including Alzheimer disease, have been associated with olfaction impairment, studies exploring how to ameliorate this impairment are limited. The aim of the present study was to determine the effect of various types of physical exercise on olfaction decline in ageing. METHODOLOGY: 99 healthy community-dwelling participants (85 women; mean (SD) age, 62.5 (5.7) years) were included. All the participants were required to complete the tests consisting of a questionnaire, cognitive test and olfaction test. RESULTS: Odor identification scores for participants who exercised regularly for more than 1 year (more than 3 times/wk; more than 30 min each time) were significantly higher than those for non-exercisers, and odor detection threshold scores were significantly higher in the exercisers. Both odor threshold and odor identification scores for those who exercised by practicing taiji (tai chi), dancing, or running were significantly better than those for participants who exercised by walking or who did not exercise. CONCLUSION: Compared with those among older people who did not exercise, measures of olfaction among older adults who exercised were better, and the type of physical exercise mattered. Therefore, if physical exercise intervention is suggested to prevent or delay olfactory deterioration in older adults, the type of physical exercise should be considered.

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BackgroundEmotional regulation is crucial to people who receive a diagnosis of methamphetamine (MA) use disorder. Although evidence that exercise improves emotional regulation is robust, little is known about whether exercise will improve emotional processing in women with MA use disorder.MethodsIn the present study, 36 women with MA use disorder aged 20 to 34 years and residing in the Drug Rehabilitation Bureau of Mogan Mountain in Zhejiang province were assigned to 1 of 2 exercise intervention groups-dancing or stationary cycling. Both types of exercise were performed at 65–75% of the maximum heart rate for 30 min. Immediately before and after the exercise bout, the participants were asked to score their feelings using a nine-point Likert scale as they viewed emotionally negative, positive, or neutral images in blocks of 20 images each, for a total of 60 images. Concurrent with viewing the images and self-rating their emotions, the women also underwent functional near-infrared spectroscopy to assess changes in brain activity.ResultsThere were no significant differences in the demographic or MA use characteristics assessed for the women between the two exercise groups. We found main effect of image valence (F2,33 = 69.61, p &lt; 0.01), significant interaction effect of time and image valence was found (F2,33 = 4.27, p &lt; 0.05) and trend increase in the self-rated emotional scale score for viewing negative images in both groups after 30-min exercise intervention, and the dancing group presented more significant trends than cycling group. In addition, activation in the dorsolateral prefrontal cortex of dancers, but not of cyclists, while viewing negative images was significantly lower after vs. before dancing (F2,33 = 5.43, p &lt; 0.05). This result suggested that 30 min of dancing decreased neural activity in women with MA use disorder while they viewed negative images specifically in a brain region known to guide the selection of appropriate behaviors, and to shift attention.Taken together, the findings of this study suggest that for women with MA abuse disorder, 30 min of dancing, rather than of stationary cycling, may ameliorate negative emotional reactions by decreasing attention to negative stimuli.

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