Table 5.
Association between indicators of SEP and malaria incidence in children aged 6 months to 10 years in Nagongera, Uganda
| Characteristic | Malaria incidence* | Crude IRR (95% CI)† | P | Adjusted IRR (95% CI)‡ | P |
|---|---|---|---|---|---|
| Mean age during follow-up | |||||
| 6 months to < 3 years | 4.1 (134) | 1 | – | 1 | – |
| 3 to < 5 years | 4.2 (177) | 1.01 (0.85–1.19) | 0.93 | 0.99 (0.82–1.20) | 0.96 |
| 5 to < 11 years | 2.3 (491) | 0.54 (0.46–0.65) | < 0.001 | 0.54 (0.46–0.65) | < 0.001 |
| Gender | |||||
| Female | 2.7 (361) | 1 | – | 1 | – |
| Male | 3.2 (441) | 1.13 (0.97–1.32) | 0.12 | 1.14 (0.97–1.35) | 0.11 |
| Wealth index | |||||
| Wealth Index I | |||||
| Poorest | 3.0 (258) | 1 | – | 1 | – |
| Middle | 3.1 (280) | 1.12 (0.90–1.40) | 0.31 | 1.16 (0.93–1.43) | 0.18 |
| Highest | 2.9 (241) | 1.05 (0.83–1.34) | 0.68 | 1.08 (0.86–1.37) | 0.51 |
| Continuous score§ | – | 0.95 (0.86–1.06) | 0.35 | 0.96 (0.88–1.06) | 0.46 |
| Wealth Index II | |||||
| Poorest | 3.2 (264) | 1 | – | 1 | – |
| Middle | 2.9 (289) | 1.03 (0.83–1.29) | 0.77 | 1.10 (0.90–1.35) | 0.33 |
| Highest | 2.9 (226) | 1.00 (0.78–1.27) | 0.98 | 1.04 (0.80–1.36) | 0.75 |
| Continuous score§ | – | 0.95 (0.84–1.07) | 0.38 | 0.97 (0.86–1.10) | 0.67 |
| Income | |||||
| Total income from agriculture in the past 12 months (UGX) | |||||
| < 100,000 | 3.1 (283) | 1 | – | 1 | – |
| 100,000 to < 300,000 | 2.5 (270) | 0.84 (0.66–1.06) | 0.14 | 0.79 (0.62–1.00) | 0.05 |
| ≥ 300,000 | 3.5 (215) | 1.13 (0.90–1.42) | 0.29 | 1.11 (0.88–1.40) | 0.37 |
| Remittances received in the past 12 months | |||||
| No | 3.1 (679) | 1 | – | 1 | – |
| Yes | 2.6 (100) | 0.88 (0.65–1.20) | 0.42 | 1.10 (0.76–1.57) | 0.62 |
| Occupation | |||||
| Primary occupation of the household head | |||||
| Agriculture or unskilled | 3.0 (576) | 1 | – | 1 | – |
| Skilled | 3.0 (203) | 0.93 (0.74–1.19) | 0.58 | 0.90 (0.66–1.23) | 0.51 |
| Main source of household income | |||||
| Agriculture or unskilled | 3.1 (628) | 1 | – | 1 | – |
| Skilled | 2.8 (118) | 0.93 (0.70–1.23) | 0.59 | 1.01 (0.69–1.48) | 0.97 |
| Remittances or other | 2.5 (33) | 0.77 (0.43–1.36) | 0.37 | 0.67 (0.38–1.19) | 0.17 |
| Education | |||||
| Female caregiver ever attended school | |||||
| No | 3.5 (188) | 1 | – | 1 | – |
| Yes | 2.9 (546) | 0.80 (0.67–0.95) | 0.01 | 0.70 (0.49–0.98) | 0.04 |
| Female caregiver's highest level of school completed | |||||
| None | 3.5 (188) | 1 | – | 1 | – |
| Incomplete primary | 3.0 (406) | 0.83 (0.69–1.01) | 0.06 | 1.26 (0.91–1.74) | 0.16 |
| Primary or higher | 2.4 (140) | 0.69 (0.53–0.91) | 0.008 | Omitted due to collinearity | – |
CI = confidence interval; IRR = incidence rate ratio; SEP = socioeconomic position; UGX = Ugandan shilling.
Malaria incidence: episodes per person-years at risk. Total person-years at risk shown in brackets.
IRR minimally adjusted for mean age during follow-up and gender.
IRR adjusted for mean age during follow-up, gender, categorical Wealth Index I, and all other SEP indicators, excluding all other wealth index variables. IRRs for the categorical Wealth Index II and continuous Wealth Indices I and II variables were adjusted for mean age during follow-up, gender, and all other indicators of SEP, excluding all other wealth index variables.
Standardized wealth index scores were created by subtracting mean index scores and dividing by the standard deviation.