Overweight and lower age at menarche: evidence from the Italian HBSC cross-sectional survey

BMC Women's Health

Table 4 Summary of results from multilevel models of age at menarche (months) among 15-year-olds across 21 regions

Factors	Model 1 adjusted for structural covariates	Model 2 addition of individual BMI	Model 3 addition of region-level overweight
Fixed effects (95% CI)
Individual level
Family affluence	−0.03 (− 0.37 to 0.30)	−0.12 (− 0.45 to 0.21)	−0.12 (− 0.45 to 0.21)
Current age (months)	0.53 (0.41 to 0.66)^*	0.53 (0.41 to 0.64)^*	0.53 (0.41 to 0.65)^*
Body mass index (BMI)	–	−0.70 (− 0.84 to − 0.56)^*	−0.70 (− 0.84 to − 0.56)^*
Region level
Prevalence of overweight (%) of 11-year-olds in 2009/2010	–	–	0.04 (− 0.11 to 0.20)
Random effects (SE)
Region-level variance	0.25 (0.58)	0.26 (0.56)	0.16 (0.72)
Region-level ICC as percentage of model 1 ICC^a	100%	106.8%	47%
Strata-level variance (north-centre-south)	1.33 (1.68)	0.68 (1.03)	1.45 (2.66)
Class-level variance	18.99 (2.68)^*	18.11 (2.61)*	18.11 (2.61)*
Residual (individual level) variance	6069.80 (155.56)	5906.23 (151.23)	5907.08 (151.58)
Log likelihood	−15,423.05	− 15,375.21	− 15,376.80
Likelihood-ratio test for change in log likelihood		p < 0.001	p < 0.01

Age at menarche is measured in self-report age in months, or current age for premenarcheal girls
Model 1: Adjusted only for current age and family affluence
Model 2: Adjusted for individual BMI measure in addition to current age and family affluence
Model 3: Adjusted for region-level prevalence of overweight (%) among 11-year-olds in 2009/2010, in addition to individual-level BMI, current age, and family affluence
CI confidence interval
^aRegion-level intraclass correlation coefficient measures the proportion of observed variation in age at menarche attributable to region level
*p < 0.05 significant result for Fixed or Random Effect

ISSN: 1472-6874