Table 1.
HALS population samples and number of deaths.
Table 2.
Cox proportional hazard model coefficients for BMI and WHtR.
Figure 1.
Mortality rate by BMI decile (source: HALS).
A clear upward trend is apparent for both sexes and obesity tends to affect the mortality rates of males more than females. Logistic regression analysis of the probability of death versus BMI category confirms a statistically significant gender difference (p<0.01).
Figure 2.
Mortality rate by WHtR decile (source: HALS).
WHtR is a significantly better predictor of mortality than BMI for males and females (i.e. steeper mortality gradient across the deciles for WHtR). Use of regression analysis showed that the difference in slopes between mortality rate and BMI (Figure 1) and WHtR (Figure 2) was statistically different (p<0.01).
Figure 3.
YLL relative to BMI 24 in male non-smokers.
There is a J-shaped association between BMI and YLL at all three of the representative ages. The optimal YLL is at BMI 24 kg/m2 for males and YLL figures relate to this reference BMI value. The ‘accepted normal’ BMI category ranges from 18.5 to less than 25 kg/m2. Surprisingly, males have slight increased YLL in part of the ‘normal’ BMI category (ie BMI from 18.5 to to 22 kg/m2). Males have increased YLL compared with females in the ‘overweight’ category (ie BMI from 25 to 30 kg/m2) at all three of the representative ages.
Figure 4.
YLL relative to BMI 26 in female non-smokers.
There is a J-shaped association between BMI and YLL at all three of the representative ages. The optimal YLL is at BMI 26 kg/m2 for females and YLL figures relate to this reference BMI value. The ‘accepted normal’ BMI category ranges from 18.5 to less than 25 kg/m2. Surprisingly, females have slight increased YLL in part of the ‘normal’ BMI category (ie BMI from 18.5 to 24 kg/m2).
Figure 5.
YLL relative to WHtR 0.5 in male non-smokers.
There is a J-shaped association between WHtR and YLL at all three of the representative ages. The optimal YLL is at WHtR 0.5 and YLL figures relate to this reference value. There is minimal increased mortality risk in the ‘OK’ range of WHtR i.e from 0.4 to 0.5. At the lower two representative ages, males have an increased risk of mortality if they are in the ‘Consider Action’ (WHtR 0.5 to 0.6) range. YLL increases markedly after WHtR 0.6 (the ‘Take Action’ category) at all three of the representative ages.
Figure 6.
YLL relative to WHtR 0.46 in female non-smokers.
There is a J-shaped association between WHtR and YLL at all three of the representative ages. The optimal YLL is at WHtR 0.46 and YLL figures relate to this reference value. There is minimal increased mortality risk in the ‘OK’ range of WHtR i.e from 0.4 to 0.5. At the lower two representative ages, females have an increased risk of mortality if they are in the ‘Consider Action’ (WHtR 0.5 to 0.6) range. YLL increases markedly after WHtR 0.6 (the ‘Take Action’ category) at all three of the representative ages.
Table 3.
Summary of YLL results based on BMI and WHtR for males and females at three representative ages: 30, 50 and 70 y.