Table 4 Relationship between being underweight and risk of malarial infection (N = 19)

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 < 0.0001^φ

.

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