Body Mass Index Growth Research Articles

Segunda encuesta antropometrica de embarazadas de la ciudad de Buenos Aires, Argentina 2010

OBJETIVOS: mostrar los resultados de la segunda encuesta antropométrica en embarazadas en Buenos Aires, Argentina. MÉTODOS: fueron medidas todas las embarazadas que concurrieron a control de salud durante una semana en los consultorios externos y centros de salud de las 12 maternidades públicas valorándose su peso, talla e índice de masa corporal (IMC). Se empleo una encuesta estructurada. RESULTADOS: fueron evaluadas 2811 embarazadas, nacidas en Argentina (49%) y en otros países (51%). Dentro de este segundo grupo, un 49% correspondió a mujeres nacidas en Bolivia (22%), Paraguay (19%) y Perú (8%). El problema nutricional más importante lo constituyó el exceso de peso con diferencias estadísticamente significativas según país de nacimiento. Se observaron dos curvas claramente diferenciadas en el IMC de embarazadas adolescentes y adultas. CONCLUSIONES: la investigación permitió obtener el perfil de estado nutricional durante la gestación empleando curvas nacionales de incremento del IMC ajustado por edad gestacional y observar el efecto de algunos determinantes sociales.

Recognition of overweight-obesity in children – are paediatricians missing the opportunity in outpatient clinics?

AimsOverweight-obesity is an emerging major health issue in children in the UK. Success of any initiative to address this and mitigate its potential health burden during adulthood relies on proactive...

Patients are harmed (again), fingers point. What's wrong?

<h3>Objectives</h3> To determine growth outcomes at 11 years of age in children born &lt;27 weeks of gestation in England in 2006 (EPICure2) and to compare growth from birth to 11 years of age for births&lt;26 weeks with those in England in 1995 (EPICure). <h3>Methods</h3> 200 EPICure2 children assessed at 11 years alongside 143 term-born controls. Growth measures from birth to 11 years were compared for births&lt;26 weeks between EPICure2 (n=112) and EPICure (n=176). Growth parameter z-scores were derived from 1990 UK standards. <h3>Results</h3> Among EPICure2 children, mean z-scores for height and weight were close to the population standards (0.08 and 0.18 SD, respectively) but significantly below those of controls: difference in mean (Δ) z-scores for weight −0.42 SD (95% CI −0.68 to –0.17), for height −0.45 SD (−0.70 to –0.20) and for head circumference (HC) −1.05 SD (−1.35 to –0.75); mean body mass index (BMI) z-score in EPICure2 children was 0.18 SD, not significantly different from controls (0.43 SD, p=0.065). Compared with EPICure, EPICure2 children born &lt;26 weeks at 11 years had higher z-scores for weight (Δ 0.72 (0.47, 0.96)), height (Δ 0.55 (0.29, 0.81)) and BMI (Δ 0.56 (0.24, 0.87)), which were not fully explained by perinatal/demographic differences between eras. Weight catch-up was greater from term-age to 2.5/3 years in EPICure2 than in EPICure (1.25 SD vs 0.53 SD; p&lt;0.001). Poor HC growth was observed in EPICure2, unchanged from EPICure. <h3>Conclusions</h3> Since 1995, childhood growth in weight, height and BMI have improved for births &lt;26 weeks of gestation, but there was no improvement in head growth.

The Impact of In Utero Exposure to Diabetes on Childhood Body Mass Index Growth Trajectories: The EPOCH Study

To examine associations between exposure to maternal diabetes in utero and body mass index (BMI) growth trajectories from birth through 13 years of age among a diverse cohort of youth. Mixed linear effects models were constructed to assess differences in BMI and BMI growth velocity from birth through 13 years of age for 95 subjects exposed to diabetes in utero and 409 unexposed subjects enrolled in a retrospective cohort study. The overall BMI growth trajectory (adjusted for sex and race/ethnicity) was not significantly different for exposed and unexposed subjects from birth through 26 months of age (P = .48). However, the overall growth trajectory from 27 months of age through 13 years differed by exposure status (P = .008), adjusted for sex and race/ethnicity. The difference was primarily due to a significantly higher BMI growth velocity among exposed youth between 10 and 13 years, increasing by 4.56 kg/m² compared with 3.51 kg/m² in the unexposed (P = .005). Control for demographic variables, socioeconomic factors, and maternal prepregnancy BMI did not alter the observed associations. Exposure to maternal diabetes in utero accelerates BMI growth in late childhood, thus increasing long-term obesity risk.

Associations between the home and school environments and child body mass index

This paper examined associations between various aspects of home and school environments and child body mass index (BMI) in the Early Childhood Longitudinal Study - Kindergarten cohort, a panel dataset of US children collected from 1998 to 2004. Using three-level growth curve modeling with a sample of approximately 11,400 children, it assessed whether these aspects were related to initial BMI and to the rate of growth of BMI over the period from kindergarten to fifth grade, independent of a large number of controls. A number of home and school factors were associated with initial BMI and the growth of BMI. Greater hours of sleep by children, more lunches eaten at school, and the adequacy of their school cafeterias and the adequacy of their school gymnasiums were all significantly associated with lower initial levels of BMI. More breakfasts typically eaten per week with their families and greater minutes of recess (free time for activity at school) were each associated with decreases in the rate of BMI growth over time, while more television watched, greater average hours of weekly maternal employment, more school lunches and school breakfasts eaten, and the adequacy of children's gymnasiums were associated with faster rates of BMI growth over the study period. The study adds to the existing literature on environmental influences on child BMI by illustrating the utility and necessity of examining multiple influences within a single analytic framework. Further research and policy efforts should continue to acknowledge the multi-etiological manner by which the environment can affect rates of child obesity.

Early Childhood Poverty, Cumulative Risk Exposure, and Body Mass Index Trajectories Through Young Adulthood

We assessed whether cumulative risk exposure underlies the relation between early childhood poverty and body mass index (BMI) trajectories. We interviewed youths and their mothers in rural upstate New York (168 boys and 158 girls) from 1995 to 2006 when the youths were aged 9, 13, and 17 years. At each interview, we calculated their BMI-for-age percentile. Early childhood poverty predicted BMI growth trajectories from ages 9 to 17 years (b = 3.64; SE = 1.39; P < .01). Early childhood poverty also predicted changes in cumulative risk (b = 0.31; SE = 0.08; P < .001). Cumulative risk, in turn, predicted BMI trajectories (b = 2.41; SE = 0.75; P < .01). Finally, after we controlled for cumulative risk, the effect of early childhood poverty on BMI trajectories was no longer significant, indicating that cumulative risk exposure mediated the relation between early childhood poverty and BMI trajectories (b = 2.01; SE = 0.94). We show for the first time that early childhood poverty leads to accelerated weight gain over the course of childhood into early adulthood. Cumulative risk exposure during childhood accounts for much of this accelerated weight gain.

Childhood obesity and proximity to urban parks and recreational resources: A longitudinal cohort study

The objective of the research was to assess how proximity to parks and recreational resources affects the development of childhood obesity through a longitudinal study. Data were collected on 3173 children aged 9–10 from 12 communities in Southern California in 1993 and 1996. Children were followed for eight years to collect longitudinal information, including objectively measured body mass index (BMI). Multilevel growth curve models were used to assess associations between attained BMI growth at age 18 and numerous environmental variables, including park space and recreational program access. For park acres within a 500m distance of children’s homes, there were significant inverse associations with attained BMI at age 18. Effect sizes were larger for boys than for girls. Recreation programs within a 10km buffer of children’s homes were significantly and inversely associated with achieved levels in BMI at age 18, with effect sizes for boys also larger than those for girls. We conclude that children with better access to parks and recreational resources are less likely to experience significant increases in attained BMI.

Interactions Between MAOA Genotype and Receipt of Public Assistance: Predicting Change in Depressive Symptoms and Body Mass Index

Response to stress is determined in part by genetically-influenced regulation of the monoamine system. We examined the interaction of a stressor (receipt of public assistance) and a gene regulating the monoamine system (MAOA) in the prediction of change in adolescent depressive symptoms and body mass index (BMI). Participants were drawn from the National Longitudinal Study on Adolescent Health (AddHealth) genetically-informative subsample. We focused on males due to the fact that males only have one MAOA allele. Growth curve analyses were conducted to assess the association between public assistance, MAOA allele, and their interaction and the intercept and slope of depressive symptoms and BMI. The results indicated that among males, MAOA allele type interacted with receipt of public assistance in the prediction of rate of change in both depressive symptoms and BMI from early adolescence through early adulthood. Males with the short MAOA allele whose families received public assistance tended to experience increased growth in depressive symptoms and BMI. Implications of the findings for understanding the relations among stress, physiology, and development are discussed.

Midlife Health and Socioeconomic Consequences of Persistent Overweight Across Early Adulthood: Findings From a National Survey of American Adults (1986-2008)

The health consequences of obesity and overweight have been well documented, but less research has examined their social and economic consequences. This paper examines the long-term consequences of early adult overweight for midlife health and socioeconomic attainment using prospective nationally representative panel data from American adults in the Monitoring the Future Study (1986-2008). Growth mixture models identified 2 distinct latent classes of trajectories of body mass index (BMI) from age 19 to 35 years: a persistently overweight class (BMI >25 kg/m(2)) and a second class exhibiting more moderate growth in BMI to age 35 years. Women (odds ratio (OR) = 2.16, 95% confidence interval (CI): 1.39, 3.36) and those from a lower childhood socioeconomic position (OR = 1.71, 95% CI: 1.30, 2.24) were more likely to be in the persistently overweight class. Compared with those in the moderately increasing BMI class, those in the persistently overweight class were more likely to have a chronic health problem at age 40 years (OR = 2.74, 95% CI: 2.20, 3.43), to have no further education beyond high school (OR = 1.33, 95% CI: 1.04, 1.69), and to have a higher odds of receiving welfare or unemployment compensation at age 40 years (OR = 1.76, 95% CI: 1.49, 2.04). These findings highlight the importance of addressing persistent obesity and overweight early in the life course.

Changes of Physical Activity Level and Physical Fitness in Adolescent Students within One Year

Previous studies focused on the relationship between physical activity level and physical fitness in adolescents were mostly from cross-sectional data. Since growth have influence on the development of physical fitness in these population. More longitudinal study would be helpful to better understand the related factors. PURPOSE: To explore the changes and sexual difference of junior high school students' physical activity level and physical fitness in one year period. Further examine the correlation between physical activity level and changes of physical fitness. METHODS: Subjects were 308 seven-grade students (145 males; 163 females) of Ta-Kuan junior high school in Taipei country, Taiwan. Physical activity level was collected using International Physical Activity Questionnaire-Adolescence in Taiwan-Show Card Version (IPAQ-A). Physical fitness was assessed as body mass index (BMI), sit-and-reach, long jump, sit-up and 800/1600-m walk/run test. The interval of two tests was one year. According to the data, we came to the conclusion through the method of descriptive statistics, independent t-test, paired t-test and Pearson's product-moment correlation. RESULTS: In average, there was no significant change of physical activity level after one year in this observed population (1834.00 +/- 1686.70 vs. 1882.03 +/- 1482.54 MET-min·wk-1). No significant differences were found on changes of physical activity level between genders. After one year, there were significant growth (p<.05) in height (3.12 +/- 2.60 cm), weight (3.61 +/- 3.40 kg), and BMI (0.62 +/- 1.20 kg·m-2). Significant improvements (p<.05) of sit-and-reach (4.51 %), long jump (1.29 %) and 800/1600-m walk/run test (10.09 % in male; 4.53 % in female) were also found. The improvements of male students' height, weight, long jump and 800/1600-m walk/run test were greater than females'. There were no significant correlations between average physical activity level and changes of physical fitness in one year period. CONCLUSIONS: When adolescent students maintained their habitual physical activity, some of their physical fitness improved with age in puberty.

Comparação do crescimento de crianças e adolescentes brasileiros com curvas de referência para crescimento físico: dados do Projeto Esporte Brasil

OBJECTIVE: To compare the growth of Brazilian children and adolescents with reference growth charts. METHODS: School-based cross-sectional study involving 41,654 students (23,328 boys and 18,326 girls) aged 7 to 17 years. Physical growth variables (body weight, height) and body mass index (BMI) were measured. Height, 50th percentile, and BMI, 85th percentile, were compared with the World Health Organization (WHO) reference values, and weight, 50th percentile, was compared with the Centers for Disease Control and Prevention (CDC) growth charts. RESULTS: Mean height and body weight of Brazilian schoolchildren were generally higher than the WHO and CDC reference values for both genders at most ages. BMI values of Brazilian schoolchildren were significantly lower than the WHO obesity values at all ages. CONCLUSION: The growth in body weight, height, and BMI of children and adolescents in the urban area of Brazil is increasingly similar to those reported in developed countries. Further prospective studies should be conducted in Brazil comparing their results with the international growth charts to enable more accurate inferences.

Comparison between the growth of Brazilian children and adolescents and the reference growth charts: data from a Brazilian project

To compare the growth of Brazilian children and adolescents with reference growth charts. School-based cross-sectional study involving 41,654 students (23,328 boys and 18,326 girls) aged 7 to 17 years. Physical growth variables (body weight, height) and body mass index (BMI) were measured. Height, 50th percentile, and BMI, 85th percentile, were compared with the World Health Organization (WHO) reference values, and weight, 50th percentile, was compared with the Centers for Disease Control and Prevention (CDC) growth charts. Mean height and body weight of Brazilian schoolchildren were generally higher than the WHO and CDC reference values for both genders at most ages. BMI values of Brazilian schoolchildren were significantly lower than the WHO obesity values at all ages. The growth in body weight, height, and BMI of children and adolescents in the urban area of Brazil is increasingly similar to those reported in developed countries. Further prospective studies should be conducted in Brazil comparing their results with the international growth charts to enable more accurate inferences.

Change of individual BMI in Switzerland and the USA: a multilevel model for growth

The aim is to analyze and compare individual body mass index (BMI) growth patterns of adults from Switzerland and the US. The analyses are based on data from two population representative longitudinal household surveys, one from Switzerland, the other from the US. Each data set contains up to four data points for each adult individual. We use multilevel models for growth. It can be shown that growth patterns are different in different cohorts in the two countries: there are only small growth differences in the youngest and oldest, but large differences in the middle ages. The individual BMI increase of the middle-aged Swiss amounts to only half of that in the comparable US individuals. Given the much higher BMI level, especially in the youngest cohort, this points to severe obesity problems in the US middle-aged population in the near future. A positive correlation between individual BMI level and growth may emphasize this fact.

References for growth and pubertal development from birth to 21 years in Flanders, Belgium

Background: Due to the secular trend in length and height, growth references need to be updated regularly. Reference charts that were until recently used in Belgium are based on samples collected more than 30 years ago, and references for body mass index (BMI) and pubertal development have not been established before.Aims: To establish contemporary cross-sectional reference charts for height, weight, BMI, head circumference, and pubertal development from birth to 21 years of age, based on a representative sample of children from Flanders, Belgium.Subjects and methods: 15 989 healthy subjects of Belgian origin, 0–25 years of age, were measured in 2002–2004. Growth curves were fitted with the LMS method, and percentiles for the pubertal development were estimated with generalized additive models on status quo data from 8690 subjects aged 6–22 years of age.Results: A positive secular trend in height and weight is observed in children above 5 years of age. Adult median height has increased by 1.2 cm/decade in boys and 0.8 cm/decade in girls; median weight by 0.9 kg/decade in boys, and 1.0 kg/decade in girls, and the weight distribution became more skewed. The BMI curve is comparable to that of other populations, except for higher percentiles. This reflects the increasing prevalence of overweight and obesity. Median age at menarche (13.0 years) has not advanced any more over the past 50 years. Median ages at menarche and B2 in girls and G2 or T4 in boys are comparable to other West European estimates, but approximately 10% enter G2/T4 before 9 years of age.Conclusions: The ongoing secular trend in height and weight makes growth charts previously used in Belgium obsolete. New representative charts for growth and pubertal development are introduced. For weight monitoring, it is advised that the now-available BMI growth charts are used.

Socioeconomic status and body mass index among Hispanic children of immigrants and children of natives.

We examined how Hispanic parents' income and education, combined with their nativity status, influenced the body mass index (BMI) of their children, compared with non-Hispanic White children and their parents. We used data from the Early Childhood Longitudinal Study, Kindergarten Class of 1998-99 to estimate linear growth curve models of children's initial BMI in kindergarten and change in BMI through fifth grade. Socioeconomic status was measured by logged household income and parental educational attainment (less than high school, high school graduate, some college, college graduate or higher). Parental education was negatively associated with children's BMI (baseline and growth) for non-Hispanic White children. Among Hispanic children, the association of parental education with growth in BMI was negative but much weaker. The weak effect of parental education was not explained by the presence of immigrants in the Hispanic population. Income was strongly negatively associated with children's BMI in kindergarten among children of Hispanic and White natives, but positively associated among Hispanic immigrant families. The positive income-BMI association among Hispanic immigrant children might reflect cultural differences that immigrant parents carry with them from their countries of origin.

Automobile traffic around the home and attained body mass index: A longitudinal cohort study of children aged 10–18 years

Objectives The objective of this study is to examine the relationship between measured traffic density near the homes of children and attained body mass index (BMI) over an eight-year follow up. Methods Children aged 9-10 years were enrolled across multiple communities in Southern California in 1993 and 1996 (n = 3318). Children were followed until age 18 or high school graduation to collect longitudinal information, including annual height and weight measurements. Multilevel growth curve models were used to assess the association between BMI levels at age 18 and traffic around the home. Results For traffic within 150 m around the child's home, there were significant positive associations with attained BMI for both sexes at age 18. With the 300 m traffic buffer, associations for both male and female growth in BMI were positive, but significantly elevated only in females. These associations persisted even after controlling for numerous potential confounding variables. Conclusions This analysis yields the first evidence of significant effects from traffic density on BMI levels at age 18 in a large cohort of children. Traffic is a pervasive exposure in most cities, and our results identify traffic as a major risk factor for the development of obesity in children.

Prevalência de sobrepeso/obesidade em crianças e adolescentes com constipação crônica funcional

OBJETIVO: Avaliar a prevalência do sobrepeso/obesidade em um grupo de crianças com constipação crônica funcional. MÉTODOS: Estudo retrospectivo com 257 crianças de dois a 15 anos com constipação crônica funcional diagnosticada segundo critérios de Roma II, atendidas consecutivamente em clínica terciária de gastroenterologia pediátrica. Informações demográficas, clínicas, diagnósticas e antropométricas foram obtidas de prontuários. O índice de massa corporal (IMC) foi calculado e utilizou-se a referência do Centers for Disease Control para determinar o percentil de IMC para idade e gênero. Crianças com percentil de IMC&gt;85 foram consideradas com sobrepeso/obesidade; as com percentis &gt; 5 e &lt;85 foram classificadas como eutróficas. RESULTADOS: Para as variáveis sociodemográficas e clínicas, não houve diferença estatisticamente significante entre os subgrupos sobrepeso/obesidade e eutrofia. A prevalência de crianças constipadas com sobrepeso/obesidade foi de 24,4%. A média dos percentis do subgrupo sobrepeso/obesidade foi 94,4±4,3; a das eutróficas foi 45,3±24,2. A prevalência de sobrepeso/obesidade foi similar em ambos os sexos e grupos etários (&lt;7 anos e &gt;7 anos). CONCLUSÕES: Os subgrupos dos eutróficos e sobrepeso/obesidade foram homogêneos nas características sociodemográficas e clínicas, sugerindo que tais variáveis não influenciaram na prevalência do excesso de peso. A prevalência estimada de sobrepeso/obesidade entre as crianças com constipação crônica funcional está dentro dos valores esperados para a população pediátrica brasileira.

Catch-up growth in body mass index is associated neither with reduced insulin sensitivity nor with altered lipid profile in children born small for gestational age

Low birth weight is a risk factor for coronary heart disease. Persons who have coronary events as adults tend to have been small at birth and thin at 2 yr of age, after which they tended to increase their body mass index (BMI). Our aim was to determine whether BMI gain is associated to alterations in insulin sensitivity and/or lipid profile in children born small for gestational age (SGA). Retrospective case-control study. We studied 78 children (mean age 7.8+/-2.5 yr): 26 SGA children with catch-up growth in BMI (CGB-SGA) (BMI= 10th to 75th centile), 26 SGA without catch-up growth (NCGB-SGA) (BMI<10th centile), and 26 appropriate for gestational age (AGA) control children (BMI: 10th to 75th centile). For each CGB-SGA child, we selected an NCGB-SGA and an AGA child of the same gender, age (within 1 yr), and pubertal status. SGA children were also subdivided into 2 groups according to post-natal catch-up growth in height (CGH). Glucose was significantly lower in NCGBSGA than AGA group (p=0.02). No significant differences in fasting insulin, fasting glucose/insulin ratio, homeostasis model assessment, quantitative insulin-sensitivity check index, and lipid profile were found among the 3 groups. HDL-cholesterol proved significantly reduced in SGA children with post-natal CGH (p=0.02). Our findings do not support the hypothesis of early alterations in insulin sensitivity and lipid metabolism in CGB-SGA subjects during childhood provided that BMI remains within the normal range. Finally, the finding of reduced HDL-cholesterol levels in CGH-SGA children suggests detrimental metabolic effects of the height gain.

Association between Serum Lipids, Blood Pressure, and Simple Anthropometric Measures in an Adult Chinese Population

Cardiovascular disease (CVD) is one of the leading causes of death in China. Although body mass index (BMI) of the Chinese population was lower than that of Western populations, it has shown a rapidly increasing trend. The objective of this study was to evaluate the association of anthropometric measurements such as BMI and waist circumference (WC) with blood pressure, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), and the prevalence of hypertension as well as dyslipidemia in Chinese adults. A cross-sectional survey in a representative sample of 881 men and 1098 women >25 years old was conducted during the period between 2002 and 2003. Height, weight, WC, resting blood pressure and serum lipid profiles including TG, TC, HDL-C and LDL-C were measured. TC, TG, LDL-C, systolic blood pressure (SBP), and diastolic blood pressure (DBP), as well as the incidence rate of dyslipidemia or hypertension, kept increasing steadily with BMI and WC. Meanwhile, HDL-C decreased with the two anthropometric measurements. Multiple regression analysis showed that both WC and BMI were independent CVD risk-associated factors and central obesity had a stronger effect on the development of CVD. Adjusted odds ratios for having dyslipidemia or hypertension also increased significantly with the growth of BMI and WC. BMI and WC had similar areas under the receiver operating characteristic curves in predicting CVD risk factors. In the Chinese population, both BMI and WC provided independent information in assessing cardiovascular risks. Chinese subjects had a higher CVD risk and lower BMI and WC than Western population. Efforts to halt the trend of increasing BMI and WC should be undertaken.

Association between circulating leptin level and anthropometric parameters in girls with adolescent idiopathic scoliosis

To investigate the correlation between the circulating leptin level and the anthropometric parameters and parameters related to pubertal growth, and to explore the role of leptin in the abnormal growth pattern in girls with adolescent idiopathic scoliosis (AIS). One hundred and twenty AIS girls selected randomly from the out-patient and in-patient departments, divided into 2 groups: Group A1 (n = 73, aged 10 - 13) and Group A2 (n = 47, aged 14 - 17), and 80 14 - 17 year-old healthy girl students receiving physical examination underwent measurement of body height and weight. Body mass index (BMI) was calculated. Peripheral fasting blood samples were collected to detect the level of leptin. The anthropometric data, pubertal status, and circulating leptin level were compared between the AIS girls and the controls. The relationships between leptin and age, menstrual status, body weight, height, BMI and Risser sign were analyzed in the AIS girls. Eighty-eight AIS girls (73%) and 14 healthy girls (18%) had a BMI score less than 18.0. The mean leptin level of Group A1 was 6.2 microg/L, significantly lower than of Group A2 (8.6 microg/L, P = 0.024). Compared with the healthy controls, the AIS girls had significantly greater corrected height (162.7 cm vs. 160.2 cm, P = 0.026), lower weight (44.3 kg vs. 53.6 kg, P = 0.01), lower BMI (17.5 kg/m(2) vs. 20.9 kg/m(2), P = 0.01), and lower circulating leptin (8.6 microg/L vs. 14.9 microg/L), even after the adjustment for age and menstrual status. An inverse correlation was observed between the leptin level and the age at menarche (AIS, r = -0.428, P < 0.001; controls, r = -0.280, P = 0.013). Whereas, positive correlations were found between leptin and age, menstrual status, body weight, height, BMI, and Risser sign (r = 0.234 - 0.506, P = 0.01 - < 0.001). AIS girls have markedly decreased circulating leptin level. Circulating leptin level is associated with body weight, BMI, and other growth parameters, suggesting that leptin may play an important role in the lower body mass in AIS girls.