LAUSR

DOI: 10.1111/iju.14697 LOH is defined as a clinical and biochemical deficiency syndrome in men of advanced age (who have had normal pubertal development and normal male secondary characteristics) associated with low testosterone, age-related comorbidities and deterioration in general health status. Among the various clinical symptoms of LOH, low libido and poor morning erection seem to be the most common. However, these reports do not include information on Asian men. There are differences between the age-related declines of sexual function of Japanese and American men. Therefore, we need to confirm which sexual symptoms are likely to occur in Japanese aging men. We carried out a cross-sectional community-based study to determine the prevalence of benign prostatic hyperplasia/lower urinary tract symptoms and to investigate the sexual function of men in Shimamaki-mura, Hokkaido, Japan, in 1992 and 2007. A total of 319 men aged >40 years who resided in Shimamaki-mura participated in the first study, and 135 men participated in the second study. In the present study, data for 448 men were available for analysis. Sexual function was evaluated using a validated questionnaire. In the validated questionnaire, all participants evaluated the following six items related to sexual function: erectile rigidity, the frequency of sex drive, the frequency of their ability to have erections when sexually stimulated, the frequency of morning erection, the degree of worry or concern about sexual function during the past 1 month and the levels of their satisfaction with sexual activity or lack of sexual activity. FT was measured by radioimmunoassay. Correlations between each sexual symptom and FT were analyzed using Spearman’s rank correlation. The differences between each sexual symptom and FT were analyzed using the Kruskal–Wallis test. According to the FT level, we divided the participants into low and high FT groups. FT values <8.5 pg/mL were defined as low FT based on the diagnostic criteria used in Japan. The difference of each symptom classified by age was analyzed comparing the two testosterone groups using the Mann–Whitney U-test. All statistical analyses were carried out using StatView 5.0 (SAS Institute, Cary, NC, USA). This study was approved by the Review Board of Sapporo Medical University Hospital (February 2007, No. 18–9). We received written informed consent from all participants. The median age of the participants was 65 years (range 40–93 years, interquartile range 57– 72 years). The median serum FT level was 9.9 pg/mL (range 0.6–26.4 pg/mL, interquartile range 5.0–13.3 pg/mL). The FT level and age were negatively correlated (r = 0.495, P < 0.001). Sexual symptoms that correlated with testosterone deficiency were the frequency of sex drive, the frequency of erection, morning erection and the rigidity of erection, as evaluated using Spearman’s rank correlation. FT levels were significantly different among these symptom scores with the Kruskal–Wallis test (P < 0.001). Among these symptoms, the frequency of sex drive (r = 0.393, P < 0.001) and the rigidity of erection (r = 0.345, P < 0.001) had significant correlations with testosterone deficiency. In the next step, the prevalences of these sexual symptoms in men with and without testosterone deficiency were evaluated by age group. The results for two highly correlated sexual symptoms are shown in Figure 1. In men aged in their 40–50s and 60s, the frequency of sex drive was significantly lower in the low FT group than in the high FT group (Fig. 1a–c). The rigidity of erection in those aged in their 40–50s and their 70s or older was significantly lower in the low FT group than in the high FT group (Fig. 1d–f). The frequency of morning erection was significantly lower in the low FT group than in the high FT group only in men aged in their 40–50s. We evaluated the symptoms of older Japanese men related to testosterone deficiency. For the diagnosis of LOH, it is necessary to confirm the presence of symptoms and signs suggestive of testosterone deficiency. These symptoms include sexual dysfunction, fatigue, impaired concentration and depression. However, we cannot always diagnose LOH in aging men by