Obesity is not protective for bones in childhood and adolescence

Although body weight is considered to positively affect bones of children and adults, recent studies suggest that overweight and obesity in childhood and adolescence reduce bone mineral content below what would be predicted based on weight and are associated with an increase in incidence of childhood fractures.     

Postmenopausal bone density and milk consumption in childhood and adolescence

Skeletal mass is a major determinant of susceptibility to osteoporotic fracture in menopause. At menopause, the skeletal mass is the resultant of the Peak Skeletal Mass (PSM) reached early adulthood minus the bone mass lost through the process of Adult Bone Loss (ABL). Current interventions for the maintenance of skeletal resilience in advanced age address the ABL peri- or postmenopausally. This study indicates that the effects of milk consumption in childhood and adolescence on bone density may manifest as higher bone density decades later in menopause. The assumed mechanism of the reported effect is through augmentation of the PSM, and acquisition of favorable nutritional habits which may influence the extent of ABL.     

Studies of atherosclerosis determinants and precursors during childhood and adolescence

At a Meeting of Investigators on Epidemiological Studies of Atherosclerosis Determinants and Precursors, which was held in Geneva on 7-9 November 1983, representatives from 26 countries reviewed the current status of epidemiological studies in this area. Particular interest was shown in the following determinants of cardiovascular disease: blood pressure, blood lipid levels, body weight, pathological studies, and tobacco use. Working papers on each determinant were prepared, and recommendations were made on areas for research, and on the need for prevention programmes and pathological studies. This article summarizes the work of the meeting.     

Estrogen-progestin contraceptive use during adolescence prevents bone mass acquisition: a 4-year follow-up study

BACKGROUND: Estrogen-progestin contraception may affect estrogen production and alter the development of peak bone mass. STUDY DESIGN: A 4-year follow-up with 122 adolescent women aged 12-19 years. The data were divided into three groups based on estrogen-progestin contraceptive (EPC) use: (i) nonusers (n=52), (ii) 1-2 years of use (n=24) and (iii) use for more than 2 years (n=46). The estrogen dose of the preparations was < or =35 mcg. Height, weight, and the amount of exercise (ratio of work metabolic rate, h/week) as well as bone mineral content (BMC) of lumbar spine and femoral neck were measured repeatedly. RESULTS: There was a significant trend showing less of an increase in the mean adjusted BMC of lumbar spine in the group of adolescent women who had used EPC for more than 2 years compared with the two other groups. In the mean adjusted BMC of the femoral neck, there was a significant trend of a smaller increase in EPC users for more than 2 years compared with 1-2 years of use. CONCLUSIONS: Long-term EPC with low-dose estrogen preparations seems to suppress normal bone mineral accrual in adolescent women.     

Obesity in childhood and adolescence: a review in the interface between adipocyte physiology and clinical challenges

Body weight is regulated by a feedback loop in which peripheral signals report nutritional information to an integratory center in the brain. The cloning of the ob gene is consistent with this concept and suggests that body fat content in adult rodents is regulated by a negative feedback loop centered in the hypothalamus. In recent years a number of additional signaling molecules secreted by adipose tissue have been discovered. These hormones, named adipocytokines, include resistin, adiponectin, and visfatin. Among the adipocytokines, adiponectin is perhaps the most interesting compound for the clinician since low adiponectin serum levels have been found in obese subjects and in particular in insulin resistant subjects. The definition and diagnosis of obesity in children and adolescents are surprisingly difficult. The level of fatness at which morbidity increases is determined on an acturial basis. In children and adolescents the degree of body fat mass depends upon ethnic background , gender, developmental stage, and age. Treatment and prevention of obesity in childhood and adolescence are major challenges for today's health care providers and societies.     

性激素对青春早期学生骨量的影响

探讨不同性激素水平对青春早期学生的骨量增长的影响,为了解性激素与青春期骨骼发育关系提供理论依据.方法 整群抽取北京市怀柔区学生共197名,采用连续3d的24h膳食问卷回顾法了解膳食钙摄入情况.采用双能量X线骨密度测量仪(DEXA)测量全身骨量并计算出骨量年增长值及骨量年增长率,同时测定男生血清睾酮与女生血清雌二醇水平,按性激素水平P25和P75为界限将研究对象分为性激素水平高、中、低3组,比较3组间的骨量年增长值及年增长率.结果 男、女生不同性激素水平组间的膳食钙总摄入差异均无统计学意义(P值均>0.05).男生低睾酮组全身骨密度的年增长值和年增长率低于中睾酮组和高睾酮组(P值均<0.01),不同睾酮组间的骨矿物含量的年增长值和年增长率差异均无统计学意义(P值均>0.05).女生高雌二醇水平组全身骨密度、骨矿物含量的年增长值和年增长率显高于中雌二醇组和低雌二醇组(P<0.05).结论 青春早期学生性激素水平对骨量增长作用有性别差异,男生体内睾酮水平较高,骨密度年增长率也较高;女生体内雌二醇水平较高者的骨量年增长率较低.     

Incidence of obesity during childhood and adolescence in a large contemporary cohort

Background and Aims

Timing of obesity development during childhood and adolescence is unclear, hindering preventive strategies. The primary aim of the present study was to quantify the incidence of overweight and obesity throughout childhood and adolescence in a large contemporary cohort of English children (the Avon Longitudinal Study of Parents and Children, ALSPAC; children born 1991-1992). A secondary aim was to examine the persistence of overweight and obesity.

Methods

Longitudinal data on weight and height were collected annually from age 7-15 years in the entire ALSPAC cohort (n = 4283), and from 3 to 15 years in a randomly selected subsample of the cohort (n = 549; ‘Children in Focus’ CiF). Incidence of overweight and obesity (BMI (Body mass index) at or above the 85th and 95th centiles relative to UK reference data) was calculated. Risk ratios (RR) for overweight and obesity at 15 years based on weight status at 3, 7, and 11 years were also calculated.

Results

In the entire cohort, four-year incidence of obesity was higher between ages 7 and 11 years than between 11 and 15 years (5.0% vs 1.4% respectively). In the CiF sub-sample, four-year incidence of obesity was also highest during mid-childhood (age 7-11 years, 6.7%), slightly lower during early childhood (3-7 years, 5.1%) and lowest during adolescence (11-15 years 1.6%). Overweight and obesity at all ages had a strong tendency to persist to age 15 years as indicated by risk ratios (95% CI (Confidence interval)) for overweight and obesity at 15 years from overweight and obesity (relative to healthy weight status) at 3 years (2.4, 1.8-3.1), 7 years (4.6, 3.6-5.8), and 11 years (9.3, 6.5-13.2).

Conclusion

Mid-late childhood (around age 7-11 years) may merit greater attention in future obesity prevention interventions.     

Predicting overweight and obesity in adulthood from body mass index values in childhood and adolescence

BACKGROUND: The Centers for Disease Control and Prevention (CDC) introduced the clinical use of the body mass index (BMI; in kg/m(2)) in growth charts for young males and females. OBJECTIVE: This study updates our previous report with the use of new CDC BMI charts and definitions of adult overweight and obesity to predict adult overweight or obesity. DESIGN: Logistic models were fitted to relate adult overweight and obesity to childhood and adolescent BMI values at each age for 166 males and 181 females in the Fels Longitudinal Study and were applied to predict adult overweight and obesity at the 75th, 85th, and 95th percentiles on the CDC charts of childhood and adolescent BMI. RESULTS: A child or adolescent with a high BMI percentile on the CDC BMI-for-age growth charts has a high risk of being overweight or obese at 35 y of age, and this risk increases with age. For example, the probability of adult obesity at the 85th percentile for young males was 相似文献