The aim of the study is to assess the association of overweight/obesity and early menarcheal age. The study comprised 2127 healthy girls aged 9 to 16 years. Menarcheal age was estimated by status quo method. The girls' body weight and height were measured and their body mass index (BMI) calculated. The diagnostic criteria of the WHO were used to define overweight and obesity. Girls with a BMI in the range of 1-2 for age and sex were considered overweight. Girls with a BMI >2 standard deviation (SD) for age and sex were considered obese. Girls with a BMI >1 SD for age and sex were considered overweight/obese. Social and economic status was analyzed according to years of education completed, parents' occupations, and the number of children in the family. Median menarcheal age was 12.83 years; 25% girls had menarche before 11.98 years and 75% by 13.69 years. By 11.21 years, 10% of girls had had menarche, and 95% by 14.91 years. Girls who had menarche before 11.98 years had higher body weight values (48.5 vs. 40.2 kg) (p<0.001), height (159.3 vs. 149.2 cm) (p<0.001), and BMI (18.9 vs. 17.8 kg/m2) (p=0.003) than their peers without menarche. Girls with menarche before 11.98 years had significantly higher BMI values than girls with menarche after 13.69 years (18.94 vs. 17.84 kg/m2) (p=0.008). Girls with menarche before 11.98 years and those after 13.69 years differ significantly in distribution of thinness (3.4% vs. 2.54%), normal weight (85.3% vs. 91.8%), and overweight/obesity (11.2% vs. 5.7%) (p=0.002). Girls who experienced early menarche are significantly more often overweight/obese. Overweight/obesity may be considered as one of the predictors for the early occurrence of menarche.

Obesity is a global public health problem. The prevalence of obesity and the risk of obesity is rising both in childhood and in adolescence throughout the world and also in Croatia. Although obesity causes short-term and long-term, direct and indirect effects on the health of an individual and the population, parents usually do not recognise it as their child's health problem. Obesity may be primary or secondary, the causes endogenic and exogenic. Obesity most often occurs as a result of an imbalance between excessive intake and reduced consumption of energy. The clinical challenges are the relatively long, asymptomatic course, the objective diagnostics of obesity and obesity-associated diseases, and the most often frustrating results of treatment. Due to the very limited possibilities of treatment in childhood, prevention is the foundation of intervention. Prevention of obesity begins with the prenatal formation or correction of incorrect dietary and lifestyle habits. Primary prevention of obesity is aimed at anthropometric monitoring and education of the healthy population. Secondary and tertiary prevention of obesity comprises specific interventions through clinical and laboratory supervision of the population at risk of developing obesity, specifically adjusted to the individual needs of the obese child. Multi-discipline, continuous and professionally coordinated preventive programmes are the foundation for resolution of the problem of obesity in childhood and adolescence, which require the engagement and cooperation of families, the health and education systems, and the support of the media and the social community.