Table 2. Estimated proportion of persons who injected drugs (PWID) in their lifetime, by survey and combined by meta-analysis, United States.
| Population | Survey | % PWID | 95% Confidence Interval | |
| Males | ||||
| NSDUH | 2.7 | 2.6 | 2.9 | |
| NHANES | 3.3 | 2.7 | 3.9 | |
| GSS | 4.9 | 4.2 | 5.6 | |
| Combined estimate | 3.6 | 2.4 | 4.8 | |
| Females | ||||
| NSDUH | 1.3 | 1.2 | 1.4 | |
| NHANES | 1.4 | 1.1 | 1.8 | |
| GSS | 2.1 | 1.7 | 2.5 | |
| Combined estimate | 1.6 | 1.1 | 2.0 | |
| Total | ||||
| NSDUH | 2.0 | 1.9 | 2.1 | |
| NHANES | 2.3 | 2.0 | 2.7 | |
| GSS | 3.4 | 3.0 | 3.8 | |
| Combined estimate * | 2.6 | 1.8 | 3.3 | |
*Q2 = 45.1, p<0.0001, I2 = 95.6.
NSDUH = National Survey of Drug Use and Health (2002–2009); NHANES = National Health and Nutrition Examination Survey (1999–2008); GSS = General Social Survey (2000 – 2008).