## 3 Results
### Association of Multifactors with Carpal Tunnel Syndrome
A questionnaire was sent to patients, obtaining 118,208 responses in 1987 and 127,466 responses in 2001. The data were analyzed using an age-adjusted logistic regression to study the relationship between CTS and occupation. In 2001, the crude incidence rate of CTS was 1.5 times higher than in 1987 but the difference was not statistically significant after subdividing by age and sex. In both years, the female/male ratio was 3:1. Incidence rates were related to the job level of women, but not of men. [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] [61] studied surgical cases of idiopathic CTS in blue- and white-collar workers and housewives, where 8801 participants took part in the research and the data were obtained from public and private hospital records in the regional database of Tuscany, Italy. Blue-collar workers presented further surgical treatment of idiopathic CTS but no relationship between sex and age influence on idiopathic CTS was found in blue-collar workers. [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] [62] investigated the effect of age, sex, and occupation on carpal tunnel decompression outcomes, where 479 patients participated. The results of the surgery were evaluated using the Brigham Hospital carpal tunnel questionnaire two weeks before surgery and six months after surgery. Cases were divided by age into four categories and two groups by occupation (repetitive and non-repetitive). Statistical analyses using the Kruskal-Wallis test to assess age and Mann-Whitney U test to assess sex and occupation were performed. No influence from age, sex, and occupation was found on the outcome of carpal tunnel decompression. Using a hospital population of 179 cleaning workers, [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], et al. [63] studied the appearance of CTS and elbow cube neuropathy (UNE) to check the differences between workers with and without CTS. The clinical and electrophysiological severity of CTS and UNE was evaluated using standardized severity scales and the symptoms were assessed with the self-administered Boston questionnaire. Univariate analysis showed that cleaners with CTS were older, had a higher BMI, and more prolonged exposure to cleaning with previous employers than those without CTS. [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] [64] reported in a study involving 1142 apprentices that the prevalence of CTS among apprentice construction workers was 8.2%, in comparison to metalworkers with 9.2%. It was determined that BMI, age, and self-reports of hard work were associated with the prevalence of CTS. The study was conducted by having participants complete a self-administered questionnaire and undergoing an electrophysiological study to assess the median nerve function. In a study with 900 selected subjects, [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] [65] determined that CTS is related to job classification or other risk factors through an occupational evaluation considering written job analysis, videotaped job analysis, deposition transcripts, and direct interviews, where 50 subjects underwent extensive electrodiagnostic testing. In the population claiming to have CTS caused by railroad occupations, there was a significant association between CTS and BMI, age, and wrist index, but not job classification. [PERSON], [PERSON], [PERSON] and [PERSON] [66] conducted a study of the factors associated with CTS in industrial workers (steel pharmacy, meat/food packaging, electronics, and plastics). Their medical history, lifestyle factors, and symptoms were evaluated using interviews and electrodiagnostic studieswere done to measure the median nerve function. The sample consisted of 111 women and 145 men without CTS. The logistic regression analysis showed that older age, female sex, relative overweight, cigarette smoking, and the vibrations associated with job tasks significantly increased the risk for dominant-hand CTS.