human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: In children there is limited underst and ing about the biological and environmental risk factors of fractures . Therefore , we aim ed to study the effect of maternal smoking on preschool children 's fractures hypothesizing that the fracture risk might be programmed during intrauterine growth in means of disturbed bone formation . A prospect i ve birth cohort included women living in Northern Finl and with an expected date of delivery between July 1st , 1985 and June 30th , 1986 ( N=9362 ) , and their offspring ( N=9432 ) .  Smoking  was inquired during pregnancy and when the offspring reached seven years of age . Information on in-hospital-treated fractures among the children was collected from the National Hospital Discharge Register ( NHDR ) . The cases who declined to participate or suffered from any bone dysplasia such as osteogenesis imperfecta or any malignancy were excluded , thus 6718 subjects ( 71.2 % ) were finally included . Poisson regression analysis with adjustment for gender , asthma , rheumatoid arthritis , socioeconomic status of the family , maternal age and body mass index ( BMI ) of the children was used to determine the association between maternal smoking during pregnancy and bone fractures . Maternal smoking during pregnancy was associated with a 1.83-fold ( 95 % CI 1.06 - 3.02 , p=0.022 ) increased risk of in-hospital-treated fractures at pre-school age . The fracture risk in childhood is perhaps increased as a result of modified bone development of the fetus due to maternal smoking Summary We assessed the intrauterine influence of maternal smoking on childhood bone mass by comparing parental prenatal and postnatal smoking habits . We observed higher bone mass in children exposed to maternal smoking , explained by higher body weight . Maternal smoking or related lifestyle factors may affect childhood weight gain rather than skeletal growth . Introduction Maternal smoking during pregnancy may adversely affect bone health in later life . By comparing the associations of maternal and paternal smoking and of prenatal and postnatal exposure with childhood bone measures , we aim ed to explore whether the suggested association could be explained by fetal programming or reflects confounding by familial factors . Methods In 5565 mothers , fathers and children participating in a population -based prospect i ve cohort study , parental smoking habits during pregnancy and current household smoking habits were assessed by postal question naires .  Total body bone mineral content ( BMC ) , bone area ( BA ) and bone mineral density ( BMD ) were measured by dual-energy X-ray absorptiometry ( DXA ) at the median age of 6.0 years ( IQR 0.37 ) . Results In confounder-adjusted models , maternal smoking during pregnancy was associated with a higher BMC of 11.6 g ( 95 % confidence interval ( CI ) 5.6 , 17.5 ) , a larger BA of 9.7 cm2 ( 95 % CI 3.0 , 16.4 ) , a higher BMD of 6.7 g/cm2 ( 95 % CI 2.4 , 11.0 ) and a higher BMC of 5.4 g ( 95 % CI 1.3 , 9.6 ) adjusted for BA of the child . Current weight turned out to mediate these associations . Among mothers who did not smoke , paternal smoking did not show evident associations with childhood bone measures . Also , household smoking practice s during childhood were not associated with childhood bone measures . Conclusions Our results do not support the hypothesis of fetal smoke exposure affecting childhood bone mass via intrauterine mechanisms . Maternal smoking or related lifestyle factors may affect childhood weight gain rather than skeletal growth Summary The study investigates the effect of physical activity ( PA ) on a composite score for fracture risk in pre-pubertal children . Low PA in children is related to the composite score for fracture risk and the pre-pubertal years seem to be a period when PA positively affects the score . Introduction This study evaluates if  PA in children is related to clustering of risk factors for fracture . Research questions are the following : ( i ) What is the effect of physical activity ( PA ) on single traits and a composite score for fracture risk ? ( ii ) Could this score be used to identify the level of PA needed to reach beneficial effects ? Methods This prospect i ve population -based study included 269 children , aged 7–9 years at baseline while 246 attended the 2-year follow-up . We estimated duration of PA by question naires and measured traits that independently predict fractures . We then calculated gender specific Z-scores for each variable . The mean Z-score of all traits was used as a composite score for fracture risk . We tested correlation between duration of PA , each trait , and the composite score and group differences between children in different quartiles of PA . Results At baseline , we found no correlation between duration of PA and any of the traits or the composite score . At follow-up , we found a correlation between PA and the composite score . Physical activity  had an effect on composite score , and children in the lowest quartiles of PA  had unbeneficial composite score compared to children in the other quartiles . Conclusion  Low PA in children is related to clustering of risk factors for fracture , and the pre-pubertal years seem to be a period when PA positively affects the composite score BACKGROUND The validity of the results of studies using retrospectively collected information on exposures is often criticized , because cases may report differently from controls even if their true exposure status is the same . This study was performed to quantify the extent to which this effect ( differential misclassification ) may occur for alcohol and cigarette consumption by pregnancy outcome . METHODS Prospect i ve as well as retrospective information on alcohol and cigarette consumption was collected for 2806 mothers resident in all 12 provinces of the Netherl and s , who gave birth between 1978 and 1979 . Changes in mean reported consumption and changes from user to non-user based on retrospective and prospect i ve information were compared for cases and controls . This was done by calculating absolute differences ( retrospective minus prospect i ve ) in reported consumption and by calculating ' misclassification odds ratios ' . Further , conventional odds ratios based on retrospective information were compared with those based on prospect i ve information . Outcome measures were stillbirth , small for gestational age ( SGA ) , congenital malformations , preterm birth and low birthweight . RESULTS The only statistically significant result was found for smoking and SGA . Mothers with an SGA child retrospectively reported a higher number of cigarettes smoked than they had prospect ively , more so than mothers of a control child . However , the odds ratios of the relation between SGA and smoking based on prospect i ve and retrospective information , respectively , were virtually the same . CONCLUSIONS Our results suggest that information bias is unlikely to have a large influence on effect estimates in studies using retrospective information on alcohol and cigarette consumption There have been no studies of smoking during pregnancy and bone mineralization in children . The objective of this population -based longitudinal study was to determine whether maternal smoking during pregnancy is associated with bone mass and other growth variables in prepubertal children . We studied 330 8-year-old male and female children representing 47 % of those who originally took part in a study of risk factors for Sudden Infant Death Syndrome in 1988 . The main outcome measures were bone mineral density measured by a Hologic QDR2000 densitometer : birth weight , placental weight , height , and weight . Maternal smoking during pregnancy was associated with deficits in growth with these children having lower height ( -1.53 cm , 95 % confidence interval [ CI ] -3.03 to -0.03 ) and a trend to lower weight ( -1.35 kg , 95 % CI -2.75 to 0.11 ) at age 8 . Furthermore , there was a disproportionate deficit in bone mass such that those children whose mothers smoked during pregnancy had lower size adjusted bone mass at the lumbar spine ( -0.019 g/cm2 , 95 % CI -0.033 to -0.005 ) and femoral neck ( -0.018 g/cm2 , 95%CI -0.034 to -0.002 ) but not total body ( -0.005 g/cm2 , 95 % CI -0.015 to 0.005 ) . This association was only present for children born at term . Mothers who smoked during pregnancy also had lower placental weight ( - 56 g , 95 % CI -95 to -17 ) , and further adjustment for placental weight led to nonsignificant results for smoking with both growth and bone parameters , suggesting that these associations may be mediated through placental size and function . Maternal smoking habit in 1996 was not significantly associated with bone mass at any site . In conclusion , this study has demonstrated a long-term negative association between maternal smoking during pregnancy and both growth and bone mass in children born at term , and suggests that the timing of exposure rather than the dose or duration is critical . If these associations are present in other population s and they persist until the attainment of peak bone mass , then our findings suggest that osteoporosis prevention programs should start very early in the life cycle 
    Output:
    
agent
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: In children there is limited underst and ing about the biological and environmental risk factors of fractures . Therefore , we aim ed to study the effect of maternal smoking on preschool children 's fractures hypothesizing that the fracture risk might be programmed during intrauterine growth in means of disturbed bone formation . A prospect i ve birth cohort included women living in Northern Finl and with an expected date of delivery between July 1st , 1985 and June 30th , 1986 ( N=9362 ) , and their offspring ( N=9432 ) .  Smoking  was inquired during pregnancy and when the offspring reached seven years of age . Information on in-hospital-treated fractures among the children was collected from the National Hospital Discharge Register ( NHDR ) . The cases who declined to participate or suffered from any bone dysplasia such as osteogenesis imperfecta or any malignancy were excluded , thus 6718 subjects ( 71.2 % ) were finally included . Poisson regression analysis with adjustment for gender , asthma , rheumatoid arthritis , socioeconomic status of the family , maternal age and body mass index ( BMI ) of the children was used to determine the association between maternal smoking during pregnancy and bone fractures . Maternal smoking during pregnancy was associated with a 1.83-fold ( 95 % CI 1.06 - 3.02 , p=0.022 ) increased risk of in-hospital-treated fractures at pre-school age . The fracture risk in childhood is perhaps increased as a result of modified bone development of the fetus due to maternal smoking Summary We assessed the intrauterine influence of maternal smoking on childhood bone mass by comparing parental prenatal and postnatal smoking habits . We observed higher bone mass in children exposed to maternal smoking , explained by higher body weight . Maternal smoking or related lifestyle factors may affect childhood weight gain rather than skeletal growth . Introduction Maternal smoking during pregnancy may adversely affect bone health in later life . By comparing the associations of maternal and paternal smoking and of prenatal and postnatal exposure with childhood bone measures , we aim ed to explore whether the suggested association could be explained by fetal programming or reflects confounding by familial factors . Methods In 5565 mothers , fathers and children participating in a population -based prospect i ve cohort study , parental smoking habits during pregnancy and current household smoking habits were assessed by postal question naires .  Total body bone mineral content ( BMC ) , bone area ( BA ) and bone mineral density ( BMD ) were measured by dual-energy X-ray absorptiometry ( DXA ) at the median age of 6.0 years ( IQR 0.37 ) . Results In confounder-adjusted models , maternal smoking during pregnancy was associated with a higher BMC of 11.6 g ( 95 % confidence interval ( CI ) 5.6 , 17.5 ) , a larger BA of 9.7 cm2 ( 95 % CI 3.0 , 16.4 ) , a higher BMD of 6.7 g/cm2 ( 95 % CI 2.4 , 11.0 ) and a higher BMC of 5.4 g ( 95 % CI 1.3 , 9.6 ) adjusted for BA of the child . Current weight turned out to mediate these associations . Among mothers who did not smoke , paternal smoking did not show evident associations with childhood bone measures . Also , household smoking practice s during childhood were not associated with childhood bone measures . Conclusions Our results do not support the hypothesis of fetal smoke exposure affecting childhood bone mass via intrauterine mechanisms . Maternal smoking or related lifestyle factors may affect childhood weight gain rather than skeletal growth Summary The study investigates the effect of physical activity ( PA ) on a composite score for fracture risk in pre-pubertal children . Low PA in children is related to the composite score for fracture risk and the pre-pubertal years seem to be a period when PA positively affects the score . Introduction This study evaluates if  PA in children is related to clustering of risk factors for fracture . Research questions are the following : ( i ) What is the effect of physical activity ( PA ) on single traits and a composite score for fracture risk ? ( ii ) Could this score be used to identify the level of PA needed to reach beneficial effects ? Methods This prospect i ve population -based study included 269 children , aged 7–9 years at baseline while 246 attended the 2-year follow-up . We estimated duration of PA by question naires and measured traits that independently predict fractures . We then calculated gender specific Z-scores for each variable . The mean Z-score of all traits was used as a composite score for fracture risk . We tested correlation between duration of PA , each trait , and the composite score and group differences between children in different quartiles of PA . Results At baseline , we found no correlation between duration of PA and any of the traits or the composite score . At follow-up , we found a correlation between PA and the composite score . Physical activity  had an effect on composite score , and children in the lowest quartiles of PA  had unbeneficial composite score compared to children in the other quartiles . Conclusion  Low PA in children is related to clustering of risk factors for fracture , and the pre-pubertal years seem to be a period when PA positively affects the composite score BACKGROUND The validity of the results of studies using retrospectively collected information on exposures is often criticized , because cases may report differently from controls even if their true exposure status is the same . This study was performed to quantify the extent to which this effect ( differential misclassification ) may occur for alcohol and cigarette consumption by pregnancy outcome . METHODS Prospect i ve as well as retrospective information on alcohol and cigarette consumption was collected for 2806 mothers resident in all 12 provinces of the Netherl and s , who gave birth between 1978 and 1979 . Changes in mean reported consumption and changes from user to non-user based on retrospective and prospect i ve information were compared for cases and controls . This was done by calculating absolute differences ( retrospective minus prospect i ve ) in reported consumption and by calculating ' misclassification odds ratios ' . Further , conventional odds ratios based on retrospective information were compared with those based on prospect i ve information . Outcome measures were stillbirth , small for gestational age ( SGA ) , congenital malformations , preterm birth and low birthweight . RESULTS The only statistically significant result was found for smoking and SGA . Mothers with an SGA child retrospectively reported a higher number of cigarettes smoked than they had prospect ively , more so than mothers of a control child . However , the odds ratios of the relation between SGA and smoking based on prospect i ve and retrospective information , respectively , were virtually the same . CONCLUSIONS Our results suggest that information bias is unlikely to have a large influence on effect estimates in studies using retrospective information on alcohol and cigarette consumption There have been no studies of smoking during pregnancy and bone mineralization in children . The objective of this population -based longitudinal study was to determine whether maternal smoking during pregnancy is associated with bone mass and other growth variables in prepubertal children . We studied 330 8-year-old male and female children representing 47 % of those who originally took part in a study of risk factors for Sudden Infant Death Syndrome in 1988 . The main outcome measures were bone mineral density measured by a Hologic QDR2000 densitometer : birth weight , placental weight , height , and weight . Maternal smoking during pregnancy was associated with deficits in growth with these children having lower height ( -1.53 cm , 95 % confidence interval [ CI ] -3.03 to -0.03 ) and a trend to lower weight ( -1.35 kg , 95 % CI -2.75 to 0.11 ) at age 8 . Furthermore , there was a disproportionate deficit in bone mass such that those children whose mothers smoked during pregnancy had lower size adjusted bone mass at the lumbar spine ( -0.019 g/cm2 , 95 % CI -0.033 to -0.005 ) and femoral neck ( -0.018 g/cm2 , 95%CI -0.034 to -0.002 ) but not total body ( -0.005 g/cm2 , 95 % CI -0.015 to 0.005 ) . This association was only present for children born at term . Mothers who smoked during pregnancy also had lower placental weight ( - 56 g , 95 % CI -95 to -17 ) , and further adjustment for placental weight led to nonsignificant results for smoking with both growth and bone parameters , suggesting that these associations may be mediated through placental size and function . Maternal smoking habit in 1996 was not significantly associated with bone mass at any site . In conclusion , this study has demonstrated a long-term negative association between maternal smoking during pregnancy and both growth and bone mass in children born at term , and suggests that the timing of exposure rather than the dose or duration is critical . If these associations are present in other population s and they persist until the attainment of peak bone mass , then our findings suggest that osteoporosis prevention programs should start very early in the life cycle 
    Output:
    