Age at menarche and its association with overweight including obesity and socio‐economic conditions of Brazilian schoolgirls: A time‐trend analysis

Abstract

This study aims to describe the time trend of age at menarche in Brazilian schoolgirls evaluated in 2007, 2012/2013 and 2018/2019, and to assess its association with having overweight, including obesity and socio-economic conditions. Three cross-sectional studies were carried out in 2007, 2012/2013 and 2018/2019 in schoolchildren enrolled between the second and ninth years of elementary school and comprising 838, 688 and 326 schoolgirls, respectively. Body mass index Z scores were calculated and categorised as either without overweight or with overweight (including obesity). The type of school (a proxy of socio-economic condition) was categorised as either public or private. Menarche data were collected using the status quo and recall methods. The mean age at menarche was estimated by survival analysis. Differences in age at menarche according to the year of survey, weight status and type of school were verified by the Log-Rank test and Cox's univariate and multiple regression. There was an increase in the prevalence of overweight in girls throughout the surveys, with 21.4% in 2007, 27.2% in 2012 and 28.5% in 2018 (p = 0.007) having overweight. There was a decrease in the mean age at menarche between 2007 and 2018/2019 (12.3 vs. 11.9 years, respectively). The mean age at menarche in girls with overweight was lower in the three time periods when compared to girls without overweight (11.9, 11.8 and 11.5 vs. 12.4, 12.4 and 12.1, respectively).Girls with overweight were more likely to have had earlier age at menarche than girls without overweight (Hazard Ratio 1.57; 95% CI 1.36; 1.80). There were no differences in the age at menarche according to the type of school. The increase in the prevalence of girls with overweight (including obesity) may be associated with the age at menarche. Girls with overweight had a higher risk of earlier age at menarche than girls without overweight.

Trends in the prevalence of obesity, overweight, and thinness among schoolchildren aged 7–14 years from southern Brazil (2002–2019)

“…The target samples were 2880 for 2012/13 and 2891 for 2018/19. However, the actual obtained samples consisted of 2469 (85.7% of the target in 2012/13) and 1544 schoolchildren (53.4% of the target in 2018/19; Matsuo et al, 2022; Motter et al, 2015).…”

“…Subsequently, 30 schools (19 public and 11 private) were selected through random sampling within each stratum. Additional details on the sampling processes can be found in other studies (Bernardo & de Vasconcelos, 2012; de Assis et al, 2005; Matsuo et al, 2022; Motter et al, 2015).…”

“…Body weight was measured using an electronic scale of 180 kg maximum capacity (Marte®, model PP 180, accuracy of 100 g) in the 2002 and 2007 surveys; and with an electronic scale of 200 kg maximum capacity (Marte®, model LC 200 PP, accuracy of 50 g) in 2012/13 and in 2018/19. Height was measured using a tape measure attached to a wall without a baseboard in 2002 (1 mm precision) and a portable stadiometer (Alturexata®, 1 mm precision) in 2007, 2012/13, and 2018/19 (Bernardo & de Vasconcelos, 2012; de Assis et al, 2005; Matsuo et al, 2022; Motter et al, 2015; Pereira et al, 2023). In all surveys, the students were wearing light clothes, barefoot, in an orthostatic position, with their heads in the Frankfurt plane (Bernardo & de Vasconcelos, 2012; de Assis et al, 2005; Matsuo et al, 2022; Motter et al, 2015; Pereira et al, 2023).…”

“…Height was measured using a tape measure attached to a wall without a baseboard in 2002 (1 mm precision) and a portable stadiometer (Alturexata®, 1 mm precision) in 2007, 2012/13, and 2018/19 (Bernardo & de Vasconcelos, 2012; de Assis et al, 2005; Matsuo et al, 2022; Motter et al, 2015; Pereira et al, 2023). In all surveys, the students were wearing light clothes, barefoot, in an orthostatic position, with their heads in the Frankfurt plane (Bernardo & de Vasconcelos, 2012; de Assis et al, 2005; Matsuo et al, 2022; Motter et al, 2015; Pereira et al, 2023).…”

Factors Influencing Age at Menarche, a School-Based Cross-Sectional Study

“…LH levels that increase faster than normal effect increasing estradiol levels which then affect reproductive maturity [17] [18]. This is in line with [19]. The study aims to describe the time trend of age at menarche in Brazilian schoolgirls evaluated in 2007, 2012/2013, and 2018/2019.…”