Table 3

Subject characteristics and crude odds ratio for being a migrant (nraw= 1543; nweighted= 3681)
Shenzhen Study Population 4th National Census -Shenzhen city Effect size4 Registered Migrants
(weighted) (N = 3,681) (n = 793) (n = 750) Migrant Status
%3 %3 n (%) n (%) Crude OR (95% C.I.)
Female 1 50.4 50.7 0.01 422 (53.2) 356 (47.5) 0.80* (0.65, 0.99)
Age group (years) 1
  18-24 13.9 13.9 0 120 (15.1) 166 (22.1) 1
 25-34 32.3 32.3 263 (33.2) 319 (42.5) 0.88 (0.66, 1.17)
 35-44 24.5 24.5 224 (28.2) 156 (20.8) 0.51*** (0.37, 0.69)
 45-54 14 14 99 (12.5) 46 (6.1) 0.34*** (0.23, 0.52)
 55-64 8.3 8.3 44 (5.5) 31 (4.1) 0.53* (0.32, 0.89)
 65+ 7.1 7 30 (3.8) 22 (2.9) 0.55* (0.30, 0.99)
Marital Status 1
 Single/separated/widowed 25.6 19 0.17 198 (25.0) 278 (37.1)
 Married 74.4 81 595 (75.0) 472 (62.9) 0.54*** (0.43, 0.67)
Education Attainment 1
 Primary or below 10.3 17.6 0.43 44 (5.5) 72 (9.6) 1.22 (0.80, 1.87)
 Middle/high school 46.5 57.4 319 (40.2) 412 (54.9) 1
 College or above 43.2 25 430 (54.2) 266 (35.5) 0.47*** (0.37, 0.58)
Occupation 1
 Executive/professional/managerial - - 148 (18.7) 76 (10.1) 0.40*** (0.29, 0.54)
 Ordinary worker - - 378 (47.7) 468 (62.4) 1
 Unemployed 35.3 39.7 0.07 267 (33.7) 206 (27.5) 0.64*** (0.50, 0.82)
Monthly income 2
 No income 27.2 - 201 (25.3) 189 (25.2) 1.08 (0.83, 1.42)
 Low income 14.8 - 72 (9.1) 130 (17.3) 1.83*** (1.29, 2.59)
 Middle income 43.3 - 341 (43.0) 343 (45.7) 1
 High income 14.7 - 179 (22.6) 88 (11.7) 0.42*** (0.29, 0.59)
Insurance status
 Uninsured 97 (12.2) 304 (40.5) 1
 Basic MIS only 422 (53.2) 275 (36.7) 0.17*** (0.13, 0.23)
 Additional MIS only 25 (3.2) 66 (8.8) 0.82 (0.48, 1.41)
 Basic + Additional MIS 212 (26.7) 98 (13.1) 0.13*** (0.09, 0.18)
Registered 53.3 - - -

Note: C.I. denotes lower and upper limit of 95% confidence interval.

1 Categories were constructed to be compatible with published census figures.

2 Income categories are constructed by quintiles, where “low” income denotes the first quintile (<20%), “middle” income denotes between second and fourth quintile (20-60%) and “high” income denotes fifth quintile or above (>60%).

3 The proportions may not add up to 100% due to rounding.

4 Effect size is a statistical measure that indicates the similarity of the sample compared to the underlying population, where an effect size of 0.1 is considered “small”, 0.3 “medium” and 0.5 “large”.

Statistical significance of p-values are denoted by * (p < 0.05), ** (p <0.01) & *** (p < 0.001).

Lam and Johnston

Lam and Johnston BMC Public Health 2012 12:868   doi:10.1186/1471-2458-12-868

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