Age group | Red cell variants | Variant | Malaria episodes | Person years of follow-up | Incidence of malaria PPY | Unadjusted | Adjusted* | ||
---|---|---|---|---|---|---|---|---|---|
IRR (95% CI) | p-value | IRR (95% CI) | p-value | ||||||
Children | Haemoglobin variant | AA | 4612 | 2762 | 1.67 | Reference | Reference | ||
AS | 818 | 620 | 1.32 | 0.77 (0.64–0.94) | 0.009 | 0.78 (0.66–0.92) | 0.003 | ||
SS | 3 | 13.4 | 0.22 | 0.16 (0.03–0.78) | 0.02 | 0.17 (0.04–0.71) | 0.02 | ||
Alpha thalassaemia variant | Normal | 3233 | 2061 | 1.57 | Reference | Reference | |||
α−/αα | 1769 | 1106 | 1.60 | 1.00 (0.85–1.18) | 0.98 | 1.04 (0.91–1.20) | 0.56 | ||
α−/−α | 251 | 150 | 1.67 | 0.97 (0.68–1.38) | 0.88 | 1.19 (0.87–1.62) | 0.27 | ||
G6PD genotype | Normal (male) | 2680 | 1597 | 1.68 | Reference | Reference | |||
Hemizygotes | 374 | 170 | 2.20 | 1.18 (0.85–1.63) | 0.33 | 0.93 (0.71–1.22) | 0.61 | ||
Normal (female) | 1768 | 1224 | 1.44 | Reference | Reference | ||||
Heterozygotes | 484 | 355 | 1.36 | 0.91 (0.70–1.18) | 0.46 | 0.80 (0.63–1.01) | 0.06 | ||
Homozygotes | 72 | 40.5 | 1.78 | 1.21 (0.60–2.44) | 0.59 | 0.89 (0.51–1.57) | 0.70 | ||
Adults | Haemoglobin variant | AA | 300 | 936 | 0.32 | Reference | Reference | ||
AS | 69 | 252 | 0.27 | 0.85 (0.56–1.30) | 0.46 | 0.99 (0.66–1.49) | 0.98 | ||
Alpha thalassaemia variant | Normal | 252 | 783 | 0.32 | Reference | Reference | |||
α−/αα | 102 | 318 | 0.32 | 1.01 (0.68–1.48) | 0.98 | 1.10 (0.76–1.59) | 0.63 | ||
α−/−α | 11 | 70.0 | 0.16 | 0.50 (0.22–1.15) | 0.10 | 0.58 (0.25–1.33) | 0.20 | ||
G6PD genotype | Normal (male) | 13 | 55.1 | 0.23 | Reference | Reference | |||
Hemizygotes | 3 | 19.4 | 0.16 | 0.66 (0.15–2.90) | 0.58 | 0.98 (0.16–5.85) | 0.98 | ||
Normal (female) | 294 | 995 | 0.30 | Reference | Reference | ||||
Heterozygotes | 73 | 191 | 0.38 | 1.26 (0.81–1.97) | 0.31 | 1.13 (0.74–1.72) | 0.58 | ||
Homozygotes | 1 | 11.2 | 0.09 | 0.39 (0.03–4.41) | 0.45 | 0.40 (0.04–3.92) | 0.43 |