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Aim: To examine the secular trend and the urban–rural disparity of spermarche among Chinese Han boys from 1995 to 2019. Methods: A total of 392 775 boys of Han ethnicity aged 11–18 years were extracted from the 1995, 2000, 2005, 2010, 2014 and 2019 Chinese National Surveys on Students' Constitution and Health. The median age at spermarche was estimated using the status quo data and probit analysis. The chi‐square, ANOVA and LSD tests were used to compare the differences between the year‐subgroups. U‐test was used to compare the difference between urban and rural areas at each year. Results: The median age at spermarche in Chinese Han boys decreased from 14.6 years in 1995 to 13.9 years in 2019 (p < 0.001). The rural boys showed a faster decreasing pace with a 1‐year advance of age at spermarche while the urban boys had only a 0.5‐year decrement, and there was still a statistically significant difference between urban–rural areas in 2019 (p < 0.001). Similar to urban–rural disparity, the age gap at spermarche between areas with different urbanisation rates became smaller over time. Conclusions: In general, spermarche in Chinese Han boys showed a decreasing trend, but the pace was slowing down. The urban–rural disparity in puberty development still existed but was gradually narrowing. [ABSTRACT FROM AUTHOR]

Aim: To assess secular trend and changes in social inequalities of children's height across nearly 50 years, when vast socio‐political changes took place in Poland. Methods: Data on schoolchildren aged 7‐18 years were collected in 1966, 1978, 1988 and 2012 in Poland. Height was standardised for age using the LMS method. Socio‐economic status (SES) was based on 4 factors: urbanisation level, mother's and father's education, and family size (number of children). Statistics included 2‐way ANOVA with post hoc Tukey's test and effect size calculations. Results: Positive secular trend in height was observed across all years. All analysed SES factors had significant effect on height which differed depending on SES category and year of Survey. Differences in height between extreme categories of SES factors decreased gradually, starting from 1978. However, only general SES in girls and urbanisation level in both sexes became insignificant in 2012. Conclusion: Improvement of living conditions across nearly 50 years was reflected in the secular trend in children's height. Despite this improvement, however, the biological effects of social inequalities, visible in differences in height, to some extent, are still present in Poland. [ABSTRACT FROM AUTHOR]

Aim: To estimate references for testicular volume measured with ultrasound and Tanner stages of pubic hair in Norwegian boys, and to compare the timing of puberty with data from similar populations.Methods: Testicular volume was derived from ultrasound measurements of testicular volume in a cross-sectional study of 514 healthy boys. A continuous testicular volume for age reference curve was estimated with the LMS method. Tanner stages for pubic hair were clinically assessed in 452 boys. Age references for pubertal milestones were estimated with probit regression.Results: Puberty onset, defined by an ultrasound testicular volume of 2.7 mL, equivalent to an orchidometer volume of 4 mL, occurred at a mean (SD) age of 11.7 (1.1) years. The reference range was 9.7 (3rd) to 13.7 years (97th percentile). Pubic hair (Tanner stage 2) appeared on average at 11.8 (1.2) years with a corresponding reference range of 9.5-14.1 years.Conclusion: The references for testicular volume measured with ultrasound are continuous in age and allow for the quantification of pubertal development. The age distribution of reaching pubertal milestones was comparable with data from other Northern European countries. [ABSTRACT FROM AUTHOR]

Aim: The study aims to investigate secular changes in adult height among Nordic reference populations during the last four decades and in parents of Swedish study participants, and to study during which growth phase(s) infancy, childhood or puberty changes in height and tempo occurred.Methods: Length and height data were obtained from publications on populations used as current and previous national height references in Denmark, Finland, Norway and Sweden. Measurements from birth until adult height and original parental heights of participants in Swedish reference populations born 1956, 1974, and 1990 were used.Results: Adult height has increased progressively in Nordic populations born in 1950s-1990s; for females by 6 mm/decade Norway, 4 mm; Sweden, 6 mm; Finland and Denmark, 7 mm; for males by 9 mm/decade, in Sweden, 5 mm; Finland, 7 mm; Denmark 8 mm; Norway, 15 mm. This was due to more growth during childhood despite earlier timing of mid-puberty. Heights of Swedish parents born 1920s-1960s increased 11 mm/decade for mothers, 14 mm/decade for fathers.Conclusion: The Nordic countries comprise some of the tallest populations in the world yet continue to show a positive secular change in adult height alongside a faster tempo of growth by earlier timing of puberty, highlighting the need to regularly update national height references. [ABSTRACT FROM AUTHOR]

Bohn et al. also confirmed that GWG is associated with BW and that being a second- or third- or later-born child implicates an impact on BW beyond the effect of maternal weight gain. Keywords: birth weight; gestational weight gain; multipara; parity; primipara; secular trend EN birth weight gestational weight gain multipara parity primipara secular trend 1094 1096 3 03/11/21 20210401 NES 210401 Abbreviations BW birth weight GWG gestational weight gain SGA small-for-gestational age BMI body mass index ECL endometrial cavity length ECW endometrial cavity width INTRODUCTION GLO:44C/01apr21:apa15678-fig-0001.jpg PHOTO (COLOR): . gl GLO:44C/01apr21:apa15678-fig-0002.jpg PHOTO (COLOR): . gl In volume, Bohn et al.1 showed that birth weight (BW) increases with birth order despite decreasing gestational weight gain (GWG) in 570 first-, 606 s-, and 162 third- or later-born infants. Finally, Bohn et al.1 concluded that "birth order must be considered a potential risk factor for higher BW, and that maternal pregnancy weight gain is not the driving factor for higher BW in siblings". They concluded that "birth order must be considered a potential risk factor for higher BW" and that "maternal pregnancy weight gain is not the driving factor for higher BW in siblings.". [Extracted from the article]

To analyse the possible changes in the prevalence of overweight and obesity comparing birth cohorts from four different decades in Finland. A retrospective longitudinal growth study. The subjects representing five birth cohorts: 1974 (n = 1109), 1981 (n = 987), 1991 (n = 586), 1995 (n = 856) and 2001 (n = 766) in the city of Tampere and three rural municipalities in Finland. Data included five consecutive height and weight measurements from 2 to 15 years of age. Normal weight, overweight and obesity at the time points were classified by body mass index (BMI, kg/m) according to international age- and gender-specific BMI cut-off points. The chi-square test was used to analyse the differences in the between birth cohorts. The combined prevalence of overweight and obesity decreased significantly in 2-year-old boys (p = 0.009) and girls (p = 0.002) from 1974 to 2001. Insignificant fluctuation was seen in 5- and 7-year-old children. Both the prevalence of obesity and the combined prevalence of overweight and obesity showed a significant increase in 12- (p = 0.031 and p < 0.001) and 15-year-old boys (p < 0.001 in both) from the 1970s to 2000s. In girls, the prevalence of obesity as well as the combined prevalence of overweight and obesity increased significantly in the age group of 12 years (p = 0.023), but not in that of 15 years. During the last three decades, overweight and obesity have become clearly more prevalent in Finnish young adolescents. This trend has been more obvious in boys than in girls. At the same time, 2-year-old children have shown an opposite trend. [ABSTRACT FROM AUTHOR]

Aim: To examine the secular trend of menarcheal age in Greek girls during the last decade. Methods: Seven hundred and fifty senior high schoolgirls were asked through a questionnaire to report their date of menarche, participation in physical activities and their weight status at menarche. The data were compared with those of a study of 1996. Results: Mean age at menarche (±SD) in 2006 was 12.29 (1.19) and in 1996 it was 12.27 (1.13) years, p = 0.73. Maternal menarcheal age was 13.02 (1.32). There was a significant correlation between age at menarche of the schoolgirls and their mothers, p < 0.0001. There was a significant difference in the age at menarche according to the schoolgirls' perceived weight status. Menarcheal age of obese girls (n = 56) was 11.73 (1.21) years, of normal weight girls (n = 474) was 12.29 (1.21) years and of lean girls (n = 220) was 12.42 (1.14) years, p < 0.001. There was no significant difference in the age at menarche between the girls that participated, 12.23 (1.19), and those that did not participate in sporting activities, 12.32 (1.19), p = 0.31. Conclusion: Levelling-off of the age at menarche over the last 10 years occurred in Greek girls living in Athens. Menarcheal age is influenced by the weight status and maternal menarcheal age. [ABSTRACT FROM AUTHOR]

Aim: To examine whether a secular trend for greater height is still observed in young Greek men. Method: Height and weight of 3982 Greek conscripts, aged 18–26 years, were measured and correlated with the level of education and place of residence. Our data were collected from May 2006 to May 2007 from pre-selected army camps all over Greece. The data were compared with those of a similar study performed in 1990. Results: Mean height (±SD) of the conscripts was 178.06 (±7.05) cm. From 1990 until 2006, mean height increased from 175.7 cm to 178.06 cm (p < 0.001), corresponding to 1.47 cm/decade. Height was positively correlated with the place of residence (p = 0.007) and the level of education (p < 0.001) of the conscripts. Conclusions: Our data show a further increase in the stature of young Greek men in the last 16 years. It appears that the male Greek population has still not exhausted its growth potential. [ABSTRACT FROM AUTHOR]