Table 2.
Prevalence (95% CI) of low birthweight according to sex of the newborn, quintiles of family income, maternal schooling and maternal skin colour, Pelotas, Southern Brazil, 1982, 1993, 2004 and 2015
| Variable | Percent low birthweight by birth cohort |
P (χ2 linear trend) | |||
|---|---|---|---|---|---|
| 1982 | 1993 | 2004 | 2015 | ||
| Sex | P = 0.003 | P = 0.005 | P = 0.044 | P = 0.089 | |
| Male | 7.2 (6.3; 8.1) | 8.0 (6.9; 9.0) | 8.1 (7.0; 9.3) | 7.6 (6.5; 8.7) | 0.476 |
| Female | 9.3 (8.2; 10.4) | 10.2 (9.1; 11.4) | 9.9 (8.6; 11.2) | 9.1 (7.8; 10.3) | 0.784 |
| Family income quintiles | P < 0.001 | P = 0.001 | P < 0.001 | P = 0.002 | |
| Q1 | 13.5 (11.5; 15.4) | 10.4 (8.5; 12.3) | 13.1 (10.8; 15.4) | 11.7 (9.5; 13.9) | 0.505 |
| Q2 | 8.6 (7.0; 10.2) | 10.4 (8.6; 12.1) | 10.5 (10.8; 15.4) | 8.0 (6.1; 9.8) | 0.806 |
| Q3 | 6.9 (5.4; 8.3) | 9.1 (7.2; 11.0) | 6.6 (4.9; 8.3) | 6.8 (5.1; 8.6) | 0.640 |
| Q4 | 6.6 (5.1; 8.0) | 9.0 (7.3; 10.8) | 7.5 (5.7; 9.2) | 8.4 (6.5; 10.2) | 0.257 |
| Q5 | 5.7 (4.4; 7.0) | 6.4 (4.9; 7.9) | 7.0 (5.3; 8.8) | 6.7 (5.0; 8.4) | 0.273 |
| Maternal skin coloura | P = 0.007 | P = 0.034 | P = 0.053 | P = 0.595 | |
| White | 7.8 (7.0; 8.5) | 8.6 (7.8; 9.5) | 8.5 (7.5; 9.4) | 8.5 (7.5; 9.5) | 0.290 |
| Brown | 10.3 (8.5; 12.1) | 10.0 (6.1; 13.9) | 8.7 (5.4; 11.9) | 7.7 (5.4; 9.9) | 0.058 |
| Black | 10.8 (8.8; 12.8) | 11.0 (8.9; 13.1) | 8.2 (6.1; 10.4) | ||
a
The test for linear trend according to maternal skin colour compares white-skinned mothers against black- or brown-skinned mothers, given that in 1982 the information was collected for two categories.