Carpal Tunnel Syndrome (CTS)
The U.S. Department of Labor defines CTS as a disorder associated with the peripheral nervous system, which includes nerves and ganglia located outside the spinal cord and brain. Carpal tunnel syndrome is the compression of the median nerve at the wrist, which may result in numbness, tingling, weakness, or muscle atrophy in the hand and fingers. The carpal tunnel receives its name from the eight bones in the wrist (called carpals), which form a tunnel-like structure. The tunnel is filled with flexor tendons, which control finger movement. The carpal tunnel also provides a pathway for the median nerve to reach sensory cells in the hand. Repetitive flexing and extension of the wrist may cause a thickening of the protective sheaths that surround each of the tendons. The swollen tendon sheaths apply increased pressure on the median nerve and produce CTS.
Two sources of data describe the magnitude and distribution of these adverse health conditions: the SOII and the case-based SENSOR program.
Annual Survey of Employers’ Reports for CTS (BLS)
CTS is more severe than the average nonfatal injury or illness case (Figure 2–50). In 2001, CTS cases involved a median of 25 days away from work compared with 6 days for all nonfatal injury and illness cases [BLS 2003a]. BLS reported 26,794 CTS cases involving days away from work in 2001 (Figure 2–45). During 1992–2001, annual rates declined 30.2% to a rate of 3.0 per 10,000 full-time workers in 2001 (Figure 2–46). Most cases involved workers who were aged 25–54 (83.6%) (Figure 2–47), female (Figure 2–48), and white, non-Hispanic (75.4%) (Figure 2–49). Two occupational groups accounted for more than 70% of all CTS cases in 2001: operators, fabricators, and laborers (36.7% or 9,808 cases) and technical, sales, and administrative support (34.2% or 9,144 cases) (Figure 2–51). Incidence rates exceeding the private-sector rate were reported for manufacturing (6.5 per 10,000 full-time workers) and finance, insurance, and real estate (3.2) (Figure 2–52). Manufacturing had consistently higher rates than other industry sectors during 1992–2001 and experienced a 33% rate reduction (Figure 2–53).
Magnitude and Trend
How did the number of CTS cases in private industry change during 1992–2001?
 | Figure 2-45 Number of CTS cases involving days away from work in private industry, 1992-2001. The annual number of CTS cases involving days away from work declined 18.9% during this period-from 33,042 cases in 1992 to 26,794 cases in 2001. CTS cases reached a high of 41,019 cases in 1993. (Sources: BLS [2003a,b].) |
How did the annual rate of CTS cases change during 1992–2001?
 | Figure 2-46 Annual rates of CTS cases involving days away from work in private industry, 1992-2001. The annual rate of CTS cases involving days away from work declined 30.2% during this period-from 4.3 per 10,000 full-time workers in 1992 to 3.0 in 2001. (Sources: BLS [2003a,b].) |
Age
How did the number of CTS cases differ by age of worker in 2001?
 | Figure 2-47 Distribution and number of CTS cases involving days away from work in private industry by age, 2001. Age data are available for 26,581 of the 26,794 BLS-estimated CTS cases involving days away from work in 2001. Workers aged 25-54 accounted for 22,213 cases or 83.6%. Workers aged 35-44 accounted for 34.0% and those aged 45-54 accounted for 30.4%. (Sources: BLS [2003a,b]; Booth-Jones et al. [2003b].) |
Sex
How did the distribution of CTS cases differ by sex of worker during 1992–2001?
 | Figure 2-48 Distribution of CTS cases involving days away from work in private industry by sex, 1992-2001. Female workers accounted for nearly 70% of CTS cases during 1992-2001, ranging from 67.0% to 71.6%, with a slightly decreasing trend. (Sources: BLS [2003a,b]; Booth-Jones et al. [2003b].) |
Race/Ethnicity
How did CTS cases differ by race/ethnicity in 2001?
 | Figure 2-49 Distribution and number of CTS cases involving days away from work in private industry by race/ethnicity, 2001. Race/ethnicity data are available for 20,327 of the 26,794 BLS-estimated CTS cases involving days away from work in 2001. White, non-Hispanic workers accounted for the majority of cases (15,335 or 75.4%). Black, non-Hispanic workers accounted for 2,704 cases or 13.3%, and Hispanic workers accounted for 1,794 cases or 8.8%. (Sources: BLS [2003a,b]; Booth-Jones et al. [2003b].) |
Severity
How did CTS cases compare with all nonfatal injury and illness cases when measured by days away from work in 2001?
 | Figure 2-50 Distribution of CTS cases and all nonfatal injury and illness cases involving days away from work in private industry by days away from work, 2001. Compared with all nonfatal injury and illness cases, CTS cases tended to involve higher percentages of long-term work loss (11-20, 21-30, and 31 or more days away from work) in 2001. Cases involving 31 or more days away from work accounted for 44.5% of CTS cases and 22% of all fatal injuries and illnesses. CTS cases involved a median of 25 days away from work in 2001-substantially greater than the median of 6 days for all nonfatal injuries and illnesses. (Sources: BLS [2003a,b]; Booth-Jones et al. [2003b]. |
Occupation
How did CTS cases differ by occupation in 2001?
 | Figure 2-51 Distribution and number of CTS cases involving days away from work in private industry by occupation, 2001. In 2001, the majority of CTS cases requiring days away from work (18,952 cases or 70.9%) occurred among two occupational groups: operators, fabricators, and laborers and technical, sales, and administrative support workers. Precision production, craft, and repair workers constituted 15.6% (4,172) of the overall CTS cases. (Sources: BLS [2003a,b]; Booth-Jones et al. [2003b].) |
Industry
How did CTS rates differ by private industry sector in 2001?
 | Figure 2-52 Incidence rate of CTS cases by private industry sector, 2001. Private industry reported a CTS incidence rate of 3.0 per 10,000 full-time workers in 2001. The rates for manufacturing (6.5 or 11,240 cases) and for finance, insurance, and real estate (3.2 or 2,204 cases) both exceeded the private-sector rate. (Sources: BLS [2003a,b]; Booth-Jones et al. [2003b].) |
How did the annual rates of CTS change by private industry sector during 1992–2001?
 | Figure 2-53 Annual rates of CTS cases involving days away from work by private industry sector, 1992-2001. The private-sector annual rate declined 30.2% during 1992-2001. Rates declined for each industry sector except wholesale trade. During this 10-year period, manufacturing had consistently higher rates than other industry sectors and experienced a 33% rate reduction. (Sources: BLS [2003a,b]; Booth-Jones et al. [2003b].) |
Case-Based Reporting of CTS (California SENSOR)
Through the SENSOR program, NIOSH provides technical and financial support to the California Department of Health Services for case-based surveillance of CTS. The California SENSOR program evaluated 3,358 CTS cases during 1998–2000. Technical, sales, and administrative support occupations consistently accounted for a disproportionate number of CTS cases in California for each of the 3 years—nearly three times the number of cases in other occupational categories (Figure 2–54). Computing (data entry) activities consistently accounted for nearly half of CTS cases in California for each of the 3 years (Figure 2–55).
Occupation
How did the number of CTS cases change in California by occupation during 1998–2000?
 | Figure 2-54 Number of CTS cases in California by occupation, 1998-2000. For each year during this period, technical, sales, and administrative support occupations consistently accounted for a disproportionately large number of CTS cases in California-nearly three times the number accounted for by other occupations. The number of CTS cases decreased during this period for four of the seven occupational groups. (Source: Harrison and Flattery [2002a].) |
Job Activity
How did the prevalence of CTS change in California by type of job activity?
 | Figure 2-55 Number of CTS cases in California by type of job activity, 1998-2000. Among the cases sampled, computing (data entry) activities consistently accounted for nearly half of all CTS cases in California for each of the 3 years during 1998-2000. Cases involved with reaching and twisting, computing (customer service), and handwriting increased from 1998 to 2000. (Source: Harrison and Flattery [2002a].) |
