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Table 1 Kaplan-Meier estimates and Cox regression of menarche according to the BMI, WC, TSF and SSFa in the total sample and in girls with recent menarche

From: Timing of menarche in Norwegian girls: associations with body mass index, waist circumference and skinfold thickness

    Unadjusted modelb Fully adjusted modelb Final modelb
N Median HR (95% CI) P HR (95% CI) P HR (95% CI) P
All girls (N = 1481)
 BMI
  Low 262 14.1 0.40 (0.30–0.55) <0.001 0.56 (0.39–0.82) 0.001 0.53 (0.38–0.75) <0.01
  Normal 960 13.1 1.00   1.00   1.00  
  High 259 12.6 1.46 (1.16–1.84) 0.001 1.45 (1.03–2.05) 0.01 1.41 (1.07–1.85) 0.01
 WC
  Low 236 13.7 0.54 (0.40–0.71) <0.001 0.93 (0.67–1.30)    
  Normal 1000 13.1 1.00   1.00    
  High 244 12.8 1.33 (1.04–1.71) 0.01 0.86 (0.59–1.24)    
 TSF
  Low 235 13.6 0.59 (0.45–0.78) <0.001 0.97 (0.72–1.30)    
  Normal 988 13.1 1.00   1.00    
  High 248 12.7 1.33 (1.04–1.71) 0.01 1.01 (0.73–1.41)    
 SSF
  Low 237 14 0.40 (0.29–0.54) <0.001 0.53 (0.37–0.75) <0.001 0.54 (0.39–0.75) <0.01
  Normal 965 13.1 1.00   1.00   1.00  
  High 273 12.8 1.21 (0.95–1.54)   1.03 (0.73–1.45)   0.96 (0.72–1.27)  
Girls with recent menarche (N = 181)
 BMI
  Low 26 13.60 0.76 (0.50–1.17)   0.92 (0.51–1.66)   0.76 (0.50–1.17)  
  Normal 118 13.10 1.00   1.00   1.00  
  High 37 12.70 1.79 (1.23–2.62) 0.001 1.19 (0.67–2.12)   1.79 (1.23–2.62) 0.003
 WC
  Low 19 13.70 0.82 (0.50–1.33) <0.001 0.99 (0.52–1.87)    
  Normal 131 13.20 1.00   1.00    
  High 31 12.60 1.96 (1.32–2.94) 0.01 1.40 (0.79–2.48)    
 TSF
  Low 36 13.50 0.80 (0.55–1.17)   1.08 (0.69–1.70)    
  Normal 119 13.10 1.00   1.00    
  High 23 12.70 1.74 (1.11–2.74)   1.11 (0.61–2.04)    
 SSF
  Low 25 13.50 0.65 (0.42–1.00) 0.050 0.66 (0.39–1.14)    
  Normal 124 13.10 1.00   1.00    
  High 32 12.70 1.71 (1.15–2.53) 0.01 1.25 (0.73–2.13)    
  1. aGrouped as low (< −1 SDS), normal (> −1 SDS – > +1 SDS) or high (> +1 SDS) BMI, WC, TSF and SSF. Estimates and models based on the total sample take into account that some girls have not yet reached menarche (censored)
  2. b Unadjusted models are simple Cox regression models for each marker separately; fully adjusted models are multiple Cox regression models including all anthropometric markers; and final models are multiple Cox regression models after backward elimination of statistically not significant covariates (p > 0.1)