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As the only species exceeding 90 m in height and 2000 years of age, Sequoia sempervirens and Sequoiadendron giganteum provide the optimal platform upon which to examine interactions among tree structure, age, and growth. We climbed 140 trees in old-growth redwood forests across California, USA, spanning a broad range of sizes and including the tallest, largest, and oldest known living individuals (i.e., 115.86 vs. 96.29 m tall, 424 vs. 582 Mg aboveground dry mass, and 2510 vs. 3240 years old for Sequoia and Sequoiadendron , respectively). We used a combination of direct measurements, hierarchical sampling, and dendrochronology to quantify tree structure and annual growth increments through old age. We also developed equations to predict aboveground attributes of standing redwoods via ground-based measurements. Compared to Sequoia , Sequoiadendron develops thicker bark on lower trunks, provisions leaves with more sapwood, and delays heartwood production throughout the crown. Main trunk wood volume growth (up to 1.6 vs. 0.9 m 3 /yr), aboveground biomass growth (up to 0.77 vs. 0.45 Mg/yr), and aboveground growth efficiency (0.55 ± 0.04 vs. 0.22 ± 0.01 kg annual growth per kg leaves, mean ± SE) are all higher in Sequoia . Two independent dimensions of structure-size and aboveground vigor-are the strongest predictors of tree-level productivity in both species. A third dimension, relative trunk size, is a significant predictor of growth in Sequoia such that trees with relatively large main trunks compared to their crowns produce more wood annually. Similar-size trees grow at similar rates regardless of latitude or elevation in tall forests of each species. Recent annual growth increments are higher than in the past for the majority of trees, and old trees are just as responsive to environmental changes as young trees. Negative growth-age relationships in previous centuries and positive growth-age relationships in recent decades reflect sampling bias and shifting disturbance regimes. Overall, we find little (if any) evidence for negative effects of old age on tree-level productivity in either species. Except for recovery periods following temporary reductions in crown size, annual increments of wood volume and biomass growth increase as redwoods enlarge with age until extrinsic forces cause tree death.

Purpose We examined whether high doses of folic acid and iron supplementation in early-to-mid pregnancy affect the risk of preterm birth, low birth weight, and small for gestational age neonates, in the mother–child cohort in Crete, Greece (Rhea study). Methods We included 1,279 women with singleton pregnancies with complete data on supplements use in early-to-mid pregnancy and birth outcomes. Anthropometric measurements at birth were obtained from medical records. Red blood cell folate concentrations in cord blood were measured in a subsample of the study population ( n  = 58). Results Sixty-six percent of the study participants reported high doses of supplemental folic acid use (5 mg/day), while 21 % reported excessive doses of folic acid use (>5 mg/day) in early-to-mid pregnancy. Daily intake of 5-mg supplemental folic acid was associated with a 31 % decrease in the risk of preterm birth (RR, 0.69; 95 % CI, 0.44, 0.99), 60 % decrease in the risk of delivering a low birth weight neonate (RR, 0.40; 95 % CI, 0.21, 0.76), and 66 % decrease in the risk of delivering a small for gestational age (SGA) neonate (RR, 0.34; 95 % CI, 0.16, 0.73). Daily doses of iron supplementation more than 100 mg were associated with a twofold increased risk for SGA neonates (RR, 2.14; 95 % CI, 0.99, 5.97). Conclusion These findings suggest that high daily doses of supplementary folic acid in early-to-mid pregnancy may be protective for preterm birth, low birth weight, and small for gestational age neonates, while high daily doses of supplementary iron may be harmful for fetal growth.

Background Children born small for gestational age (SGA) experience higher rates of morbidity and mortality than those born appropriate for gestational age. In Latin America, identification and optimal management of children born SGA is a critical issue. Leading experts in pediatric endocrinology throughout Latin America established working groups in order to discuss key challenges regarding the evaluation and management of children born SGA and ultimately develop a consensus statement. Discussion SGA is defined as a birth weight and/or birth length greater than 2 standard deviations (SD) below the population reference mean for gestational age. SGA refers to body size and implies length-weight reference data in a geographical population whose ethnicity is known and specific to this group. Ideally, each country/region within Latin America should establish its own standards and make relevant updates. SGA children should be evaluated with standardized measures by trained personnel every 3 months during year 1 and every 6 months during year 2. Those without catch-up growth within the first 6 months of life need further evaluation, as do children whose weight is ≤ -2 SD at age 2 years. Growth hormone treatment can begin in SGA children > 2 years with short stature (< -2.0 SD) and a growth velocity < 25th percentile for their age, and should continue until final height (a growth velocity below 2 cm/year or a bone age of > 14 years for girls and > 16 years for boys) is reached. Blood glucose, thyroid function, HbA1c, and insulin-like growth factor-1 (IGF-1) should be monitored once a year. Monitoring insulin changes from baseline and surrogates of insulin sensitivity is essential. Reduced fetal growth followed by excessive postnatal catch-up in height, and particularly in weight, should be closely monitored. In both sexes, gonadal function should be monitored especially during puberty. Summary Children born SGA should be carefully followed by a multidisciplinary group that includes perinatologists, pediatricians, nutritionists, and pediatric endocrinologists since 10% to 15% will continue to have weight and height deficiency through development and may benefit from growth hormone treatment. Standards/guidelines should be developed on a country/region basis throughout Latin America.

Aim: To study the relationship between insulin sensitivity and growth response in short children born small for gestational age (SGA) treated with growth hormone (GH). Methods: Randomized, open-label, 24-month intervention study in 40 short prepubertal SGA children [age (mean ± SD) 5.3 ± 1.5 years], who either remained untreated (n = 20) or were treated with GH (66 µg/kg/day; n = 20). Changes in fasting glucose, insulin, quantitative insulin sensitivity check index (QUICKI), IGF-1 and leptin after 1 and 2 years were studied. Results: Mean height SDS increased from –3.3 ± 0.7 to –2.3 ± 0.7 after 1 year, and to –1.9 ± 0.7 after 2 years of treatment. QUICKI decreased significantly (p = 0.008) in the first year of GH treatment and stabilized in the second year. Baseline QUICKI was positively associated (r = 0.40; p < 0.05) with the change in height SDS in the first year. Conclusion: Higher insulin sensitivity at the start of GH therapy is associated with greater first-year growth response to GH, and could be a promising parameter in selecting prepubertal short SGA children for GH treatment. However, this finding needs to be confirmed in larger studies.

Short stature is not the only problem faced by children born small for gestational age (SGA). Being born SGA has also been associated with lowered intelligence, poor academic performance, low social competence and behavioural problems. This paper summarizes the results of a randomized, double-blind, growth hormone (GH) dose-response study (1 or 2 mg/m2/day [ approximately 0.035 or 0.07 mg/kg/day]) on growth, intelligence quotient (IQ) and psychosocial functioning in 79 children born SGA at the start, and after 2 and 8 years of GH therapy, and addresses the associations with head circumference. Mean age at start of therapy was 7.4 years; mean duration of GH treatment was 8.0 years. In 2001, 91% of children born SGA had reached a normal height (> -2.0 standard deviation score [SDS]). Block-design s-score (Performal IQ) and Total IQ score increased (p < 0.001 for both indices) from scores significantly lower than those of Dutch peers at the start of therapy (p < 0.001) to scores that were comparable to those of Dutch peers in 2001. Vocabulary s-score (Verbal IQ) was normal at the start of therapy and remained so over time. Externalizing Problem Behaviour SDS and Total Problem Behaviour SDS improved during GH therapy (p < 0.01-0.05) to scores comparable to those of Dutch peers. Internalizing Problem Behaviour SDS was comparable to that of Dutch peers at the start of therapy and remained so, whereas Self-Perception improved from the start of GH therapy until 2001 (p < 0.001), when it reached normal scores. Head circumference SDS at the start of GH therapy and head growth during GH therapy were positively related to all IQ scores (p < 0.01), whereas neither were related to height SDS at the start of, or to its improvement during, GH therapy. A significant improvement in height and head circumference in children born SGA was seen after only 3 years of GH therapy, in contrast to randomized SGA controls. In conclusion, most children born SGA showed a normalization of height during GH therapy and, in parallel to this, a significant improvement in Performal IQ and Total IQ. In addition, problem behaviour and self-perception improved significantly. Interestingly, Performal, Verbal and Total IQ scores were positively related to head circumference, both at the start of, and during, GH therapy; head circumference increased in GH-treated children born SGA, but not in untreated SGA controls. These results are encouraging but also warrant confirmational studies and further investigations into the effects of GH on the central nervous system.

Several studies performed in the last 15 years have shown that growth hormone (GH) induces a profound catch-up in height in short children born small for gestational age (SGA). We know from more recent studies that final height can be normalized through GH treatment. In Europe, GH is now a recognized indication, enabling treatment of short children born SGA. Treatment is given to the most severe growth-retarded children after the age of 4 years. A dose of 0.035 mg/kg per day is recommended. However, in our opinion a higher dose would be more efficient in very short children, especially if they are treated later in childhood.

Recent reports have shown that high-dose growth hormone (GH) treatment in short children born with small for gestational age (SGA) resulted in a pronounced acceleration of linear growth. We describe the results of multicenter trials of recombinant human GH (rhGH) treatment in short SGA children in Japan. Two clinical studies were performed and the results were combined. Study 1 comprised 104 SGA children and study 2 comprised 61 SGA children. The patients were divided into three groups: group 1 consisted of 20 patients (13 boys and 7 girls) who received rhGH 25 microg/kg per day six or seven times per week in the first year and 50 microg/kg per day in the second year and thereafter; group 2 consisted of 48 patients (28 boys, 20 girls) who received rhGH 45/50 microg/kg per day; group 3 consisted of 44 patients (28 boys, 16 girls) who received 90/100 microg/kg per day. The mean increments in height SDS were 0.46, 0.67 and 0.94 SD in boys and 0.49, 0.79 and 0.93 SD in girls in groups 1, 2 and 3, respectively. The mean increment in height SDS at 2 years in group 3 was significantly greater than that in group 1, but it was not significantly different from that in group 2 in boys and girls. Our data demonstrated that high-dose GH administration significantly improved height velocity and height SDS in short SGA children. Additional studies are necessary to optimize a long-term GH treatment regimen and combined luteinizing hormone releasing hormone analog treatment for final height. Careful observation is also necessary to assess the metabolic effects of high-dose GH, especially on carbohydrate metabolism.

The past half-century has seen enormous changes in the demographic makeup of Latin America and the Caribbean (LAC). In the 1950s, LAC had a small population of about 160 million people, less than today's population of Brazil. Two-thirds of Latin Americans lived in rural areas. Families were large and women had one of the highest fertility rates in the world, low levels of education, and few opportunities for work outside the household. Investments in health and education reached only a small fraction of the children, many of whom died before reaching age five. Since then, the size of the LAC population has tripled and the mostly rural population has been transformed into a largely urban population. There have been steep reductions in child mortality, and investments in health and education have increased, today reaching a majority of children. Fertility has been more than halved and the opportunities for women in education and for work outside the household have improved significantly. Life expectancy has grown by 22 years. Less obvious to the casual observer, but of significance for policy makers, a population with a large fraction of dependent children has evolved into a population with fewer dependents and a very large proportion of working-age adults. This overview seeks to introduce the reader to three groups of issues related to population aging in LAC. First is a group of issues related to the support of the aging and poverty in the life cycle. Second is the question of the health transition. Third is an understanding of the fiscal pressures that are likely to accompany population aging and to disentangle the role of demography from the role of policy in that process.

First published in 1999.This volume is the third of a series devoted to the first years of the child's development, the two others being concerned with the beginnings of intelligence and the child's construction of reality (La naissance de intelligence chez Venfant and La construction du réel chez Venfant).

Joining Society asks precise questions: To what are the young socialized? Which skills, modes of thinking or action are required from them and what are their developmental value? Socialization tends to be viewed within the confines of a particular geographical or cultural situation. The multi-national list of contributors brings an international perspective to the problem of socialization to work and to adult life, while at the same time emphasizing the common issues that face youth around the world. Some of the topics addressed are the rules and roles involved in socialization, attaining personal agency through collective activity, use of new technologies, and the role of intergenerational relationships. This book sheds new light on the processes through which society may hope to intervene in positive ways with today's youth.