Table 4.
Relationship between being underweight and risk of malarial infection (N = 19)
| Author, year, reference | WAZ cutoff | Malaria outcome | Risk estimate comparing children below and above WAZ cutoff | Risk |
|---|---|---|---|---|
| Akiyama 2016 [46] | ≤ − 2 | Asymptomatic malaria confirmed by PCR | OR = 1.33 (95% CI = 0.53–3.30) | No impact |
| Arinaitwe 2012 [48] | − 1 and −2 | Pf malaria, fever and a positive blood smear | IRR = 1.09 (95% CI 0.95–1.25), P = 0.24 | No impact |
| < − 2 | Pf malaria, fever and a positive blood smear | IRR = 1.12 (95% CI 0.86–1.46), P = 0.39 | No impact | |
| Ayana 2015 [49] | < − 2 | Malaria by RDT | “Non-significant association” reported | No impact |
| Custodio 2009 [30] | < − 2 | Pf malaria parasitemia prevalence | “Non-significant association” reported | No impact |
| Deen 2002 [10] | < − 2 | Malaria episode (fever ≥ 37.5 °C or parasitemia > 5000/μL) | RR = 1.01 (95% CI = 0.82–1.26) | No impact |
| Deribew 2010 [51] | < − 2 | Pf malaria (any parasitemia) | AOR = 0.9 (95% CI = 0.7–1.2), P = 0.90 | No impact |
| Ehrhardt 2006 [11] | < − 2 | Fever | AOR = 1.59 (95% CI = 1.13–2.23), P = 0.008 | Increased |
| < − 2 | Clinical malaria (fever ≥ 37.5 °C plus any parasitemia) | AOR = 1.67 (95% CI = 1.10–2.50), P = 0.009 | Increased | |
| < − 2 | Anaemia (Haemoglobin < 11 g/dL) | AOR = 1.68 (95% CI = 1.38–2.04), P < 0.0001φ | . | |
| El Samani 1987 [52] | Weight-for-age 75–89% (mild) | History of malaria in past 2 months | AOR = 1.20 (95% CI = 0.70–2.00) | No impact |
| Weight-for-age < 75% (moderate) | History of malaria in past 2 months | AOR = 2.10, (95% CI = 1.10–4.00) | Increased | |
| Fillol 2009 [27] | < − 2 | Clinical malaria (fever ≥ 37.5 °C plus parasitemia ≥ 3000/μL) | “Non-significant association” reported | No impact |
| < − 2 | High density parasitemia (geometric mean ≥ 300/μL) | AOR = 0.96 (95% CI = 0.35–2.66), P = 0.94 | No impact | |
| Jeremiah 2007 [53] | < − 2 | Malaria by blood smear | RR = 1.02 (95% CI = 0.34–2.37), P < 0.02 | Increased |
| Kateera 2015 [54] | < − 2 | Pf malaria (any parasitemia) | “Non-significant association” reported | No impact |
| Mitangala 2013 [21] | < − 2 | Pf malaria parasitemia (≥ 5000/μL) | AOR = 0.85 (95% CI = 0.53–1.35), P = 0.49 | No impact |
| Muller 2003 [18] | ≤ − 2 | Pf malaria (fever plus parasitemia ≥ 1/μL) | RR = 1.0 (95% CI = 0.9–1.1), P = 0.98 | No impact |
| ≤ − 2 | Pf malaria (fever plus parasitemia ≥ 5000/μL) | RR = 1.0 (95% CI = 0.9–1.2), P = 0.68 | No impact | |
| ≤ − 2 | Pf malaria (fever plus parasitemia ≥ 100,000/μL) | RR = 0.8 (95% CI = 0.5–1.4), P = 0.49 | No impact | |
| Nyakeriga 2004 [6] | < − 2 | Pf malaria (fever plus any parasitemia) | IRR = 1.33 (95% CI = 0.64–2.70), P = 0.44 | No impact |
| < − 2 | Pf malaria (fever plus any para < 1 year, > 2500/μL > 1 year) | IRR = 0.28 (95% CI = 0.51–3.17), P = 0.60 | No impact | |
| Snow 1991 [17] | < − 2 | Clinical malaria (fever plus any parasitemia) | “Non-significant association” reported | No impact |
| < − 2 | Asymptomatic malaria parasitemia | “Non-significant association” reported | No impact | |
| Sumbele 2015 [57] | < − 2 | Clinical malaria parasitemia | Underweight vs. Non: 21.6% vs. 8.2%, P = 0.007 | Increased |
| < − 2 | Asymptomatic malaria parasitemia | Underweight vs. Non: 21.6% vs. 27.5%, P = 0.44 | No impact | |
| Tonglet 1999 [32] | < − 2 | Clinical malaria without lab confirmation in < 9 m | AOR = 1.31 (95% CI = 0.68–1.94) | No impact |
| < − 2 | Clinical malaria without lab confirmation in ≥ 9 m | AOR = 0.68 (95% CI = 0.24–1.11) | No impact | |
| Verret 2011 [22] | (≥ − 1 and < 0) | Pf malaria risk of recurrent parasitemia | HR = 0.65 (95% CI = 0.37–1.15), P = 0.137 | No impact |
| (≥ − 2 and < − 1) | Pf malaria risk of recurrent parasitemia | HR = 0.86 (95% CI = 0.45–1.62), P = 0.636 | No impact | |
| < − 2 | Pf malaria risk of recurrent parasitemia | HR = 1.01 (95% CI = 0.54–1.89), P = 0.969 | No impact | |
| William 1997 [31] | < − 2 | Clinical malaria (fever plus parasitemia ≥ 1000/μL) | IRR = 1.1 (95% CI = 0.57–2.1)*, P = 0.8 | No impact |
| < − 2 | Clinical malaria (fever plus parasitemia ≥ 1000/μL) | IRR = 1.3 (95% CI = 0.9–1.9)**, P = 0.2 | No impact | |
| < − 2 | P. vivax malaria | IRR = 2.6 (95% CI = 1.5–4.4)*, P < 0.0001; | Increased | |
| < − 2 | P. vivax malaria | IRR = 1.3 (95% CI = 0.9–2.0)**, P = 0.2 | No impact |
Pf Plasmodium falciparum, WAZ weight-for-age Z-scores, CI confidence interval, OR odds ratio, HR hazard ratio, RR risk ratio, IRR incidence rate ratio, AOR adjusted odds ratio
φLimited to anaemia;*6 months preceding anthropometric assessment; **6 months following anthropometric assessment