Childhood body size and pubertal timing in relation to adult mammographic density phenotype

Background: An earlier age at onset of breast development and longer time between pubertal stages has been implicated in breast cancer risk. It is not clear whether associations of breast cancer risk with puberty or predictors of onset of puberty, such as weight and height, are mediated via mammographic density, an important risk factor for breast cancer. Methods: We investigated whether childhood body size and pubertal timing and tempo, collected by questionnaire, are associated with percentage and absolute area mammographic density at ages 47-73 years in 1105 women recruited to a prospective study. Results: After controlling for adult adiposity, weight at ages 7 and 11 years was strongly significantly inversely associated with percentage and absolute dense area (p trend < 0.001), and positively associated with absolute nondense area. Greater height at age 7, but not age 11, was associated with lower percentage density (p trend = 0.016). Later age at menarche and age at when regular periods were established was associated with increased density, but additional adjustment for childhood weight attenuated the association. A longer interval between thelarche and menarche, and between thelarche and regular periods, was associated with increased dense area, even after adjusting for childhood weight (p trend = 0.013 and 0.028, respectively), and was independent of age at pubertal onset. Conclusions: Greater prepubertal weight and earlier pubertal onset are associated with lower adult breast density, but age at pubertal onset does not appear to have an independent effect on adult density after controlling for childhood adiposity. A possible effect of pubertal tempo on density needs further investigation

Body fat at pubertal genital stage 2: A comparison between Spanish and Mexican boys

Background/Objectives: To compare body fat mass at the same stage of pubertal maturation, genital stage 2 (G2), in a Spanish and in a Mexican sample of boys. Subjects/Methods: Data from Spain (n = 177) were from aprevious longitudinal clinical follow-up and data from Mexico (n = 91) from a cross-sectional study. Subjects were grouped according to the presence of G2 at similar ages. Spanish sample was divided into boys with G2 at age 12 (n = 60), 13 (n = 74) and 14 (n = 43). In Mexican sample, 23 boys were at G2 at 12 years, 38 at age 13 and 30 at 14 years. Height, weight, upper arm circumference and four skinfold thicknesses were recorded. Genital development was assessed (Tanner scale). Sum of four skinfolds (SUM), body mass index (BMI), percentage of body fat (%BF) and extremity/ trunk skinfold ratio (ETR = (triceps+biceps)/(subscapular+suprailiac)) was calculated. Results: When comparing subjects with different ages at G2 from the same country, or with the same age at G2 from different countries, no significant differences were found in adiposity variables (%BF, SUM), nor in BMI. Nevertheless, there were differences in body fat distribution: ETR was higher in Spanish boys (P < 0.001), because of their greater triceps skinfold thickness (P = 0.013), and due to the greater trunk fat stores in Mexican boys (P < 0.01, subscapular and suprailiac skinfolds). Conclusions: There is a subcutaneous fat mass store characteristic of G2 in boys, which is not only independent of age, but is also observable in two different populations

A double blind, placebo controlled study of the effects of low dose testosterone undecanoate on the growth of small for age, prepubertal boys.

OBJECTIVE--To assess whether very low doses of testosterone can accelerate growth without an undue advance in bone age in prepubertal boys with constitutional delay of growth. SUBJECTS--23 prepubertal boys aged 11-14 years with height at or below the third centile for chronological age. DESIGN--Randomised, double blind trial comparing oral testosterone undecanoate 20 mg once daily versus placebo for six months. The 18 months' observation period of each subject comprised a six month pretreatment period, followed by a six month treatment (testosterone undecanoate or placebo) period, and a six month period after termination of treatment. OUTCOME MEASURES--At intervals of six months standing and sitting height were measured. Bone age, pubertal stage, weight, and lean body mass were also determined. Growth hormone, luteinising hormone, and follicle stimulating hormone secretion and testosterone concentration were measured before, after, and six months after treatment. RESULTS--Boys taking testosterone undecanoate (n = 11) showed a significantly greater height velocity (mean (SEM) 5.84 (0.53) cm/year) and sitting height velocity (3.54 (0.57) cm/year) during treatment than the placebo treated boys (n = 12, height velocity = 3.38 (0.22) cm/year, sitting height velocity = 1.58 (0.19) cm/year. There were no significant differences between the groups regarding changes in growth hormone, gonadotrophins, testosterone, or dihydrotestosterone concentrations. Bone age was not advanced significantly more rapidly in either group. CONCLUSIONS--There is accelerated gain in height during six months of treatment with low dose testosterone undecanoate, without a significantly greater rise in bone age compared with controls. Testosterone undecanoate is a safe, well tolerated, and effective treatment in the management of constitutional delay of growth

Mapping the Distortions in Time and Space: The French Railway Network 1830-1930

International audienceAccessibility is frequently used in transportation planning to measure the efficiency of new infrastructure in terms of travel time and population served. In this article, the authors apply accessibility concepts based on the geo-historical angle. The aim of this study is to investigate the relationships between population dynamics and the railway expansion from 1830 to 1930. Their approach considers a local scale composed of some 36,000 French communes for the demographic data and more than 28,000 kilometers for the railway network. The methodological framework of this database is based on historical geographic information systems completed by anamorphosis analysis. In this way, they are able to map the changing contours of accessibility from the local to the regional and national scales for historical time