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Table 2 Anthropometric Risk Factors for Low Birth Weight

From: Mid-arm muscle area and anthropometry predict low birth weight and poor pregnancy outcomes in Tanzanian women with HIV

Characteristics N Univariate Multivariatea
RR (95% CI) P-Value RR (95% CI) P-Value
Maternal weight change - overall (slope)
 Tertile 1 47 Reference 0.003^ Reference 0.29^
 Tertile 2 30 0.62 (0.40, 0.97)   0.62 (0.40, 0.96)  
 Tertile 3 25 0.53 (0.33, 0.85)   0.61 (0.38, 0.98)  
Maternal weight change - 2nd trimester (slope)
 Tertile 1 38 Reference 0.01& Reference 0.60^
 Tertile 2 26 0.67 (0.41, 1.08)   0.66 (0.41, 1.06)  
 Tertile 3 22 0.58 (0.35, 0.97)   0.67 (0.40, 1.12)  
BMI change - overall (slope)
 Tertile 1 48 Reference 0.001& Reference 0.11&
 Tertile 2 34 0.69 (0.45, 1.05)   0.66 (0.44, 1.01)  
 Tertile 3 21 0.44 (0.27, 0.72)   0.45 (0.27, 0.74)  
MAMA mean (cm)
  ≤ 33.1 91 Reference   Reference  
  > 33.1 60 0.70 (0.51, 0.96) 0.0002^ 0.68 (0.50, 0.94) 0.009^
Mama change - overall (slope)
 Tertile 1 45 Reference 0.85^   
 Tertile 2 48 1.04 (0.70, 1.54)    
 Tertile 3 42 0.93 (0.62, 1.40)    
MAMA change - 2nd trimester (slope)
 Tertile 1 38 Reference 0.87^   
 Tertile 2 33 0.84 (0.53, 1.32)    
 Tertile 3 37 0.97 (0.63, 1.50)    
MUAC mean (cm)
  ≤ 26 cm 99 Reference   Reference  
  > 26 cm 52 0.61 (0.44, 0.84) 0.0001^ 0.62 (0.45, 0.86) 0.0006^
MUAC change - overall (slope)
 Tertile 1 36 Reference 0.64^   
 Tertile 2 27 0.73 (0.45, 1.19)    
 Tertile 3 34 0.94 (0.59, 1.47)    
MUAC change - 2nd trimester (slope)
 Tertile 1 30 Reference 0.66^   
 Tertile 2 23 0.75 (0.44, 1.27)    
 Tertile 3 30 0.98 (0.60, 1.60)    
Adherence to iron supplementation
  < Median 80 Reference   Reference  
  ≥ Median 77 0.85 (0.63, 1.14) 0.03^ 0.94 (0.69, 1.28) 0.34^
  1. ^ Test for Trend
  2. & Association was significantly non-linear. P-value corresponds to test for overall significance
  3. aMultivariate Model adjusted for all variables in the univariate with a p-value less than 0.20 plus maternal age (< 28, ≥ 28 years); gestational age (< 25, ≥ 25 weeks);WHO stage (1,2,3,4); family member with diabetes, previous low birth weight baby, previous caesarian delivery, previous baby died with first 7 days, malaria during pregnancy, repeated fever during this pregnancy, and hypertension during this pregnancy. Anthropometric variables (weight, BMI, MAMA) were entered into separate multivariate models. Where both mean and change (slope) variables are significant they were both entered into the same model (e.g. weight and weight change)