Decreased bone mineral density in adults born with very low birth weight: a cohort study

Preterm birth reduces the incidence of atopy in adulthood

BACKGROUND

Immunologic pathways are primed in early life. Preterm birth can influence this process and thereby affect whether a person will have atopy later in life. Previous studies on the effects of preterm birth on atopy in adulthood have been inconclusive and limited to children or subjects born moderately preterm.

OBJECTIVE

Our aim was to compare the incidence of atopy among young adults who were born preterm and at very low birth weight (≤ 1500 g) with that of term-born young adults (control subjects).

METHODS

The study comprised 166 adults who were born preterm and at very low birth weight and 172 control subjects, all of whom were from the Helsinki Study of Very Low Birth Weight Adults. We assessed atopic predisposition at ages 18 to 27 years using skin prick tests for 6 common aeroallergens and measurements of serum concentrations of total IgE and 3 types of allergen-specific (cat, birch, and timothy) IgE. We asked the subjects whether they had been given a diagnosis of asthma or allergic rhinitis or had atopic eczema and analyzed data by using logistic or linear regression, adjusting for potential confounding factors.

RESULTS

The risk for having at least 1 positive reaction on a skin prick test was reduced (adjusted odds ratio, 0.43; 95% CI, 0.23-0.79, P = .007), and the concentration of cat-specific IgE was less (25% less; 95% CI, 43% to 2.3% less; P = .033) in sera from very-low-birth-weight subjects compared with that seen in sera from control subjects. Within the very-low-birth-weight group, those born at an earlier gestational age were less likely to have positive skin prick test reactions (adjusted odds ratio for 1 week, 0.82; 95% CI, 0.68-0.98, P = .029) and less likely to have high levels of allergen-specific IgE. Cumulative incidences of atopic disease were similar between adults of very low birth weight and control subjects.

CONCLUSIONS

Young adults born prematurely and at very low birth weight have a lower incidence of atopy than adults who were born full term. This finding supports the hypothesis that the risk for atopy is determined during early stages of development.

Intima-media thickness and flow-mediated dilatation in the Helsinki study of very low birth weight adults

BACKGROUND

Adults born at a very low birth weight (VLBW) (< 1500 g), compared with those born at term, bear risk factors for cardiovascular disease, including higher blood pressure and insulin resistance.

OBJECTIVE

We studied, in young adults born at a VLBW, early signs of an accelerated atherosclerotic process and the relationship of these signs with postnatal growth.

METHODS

We compared 92 with a VLBW with 68 who were born at term. At age 18 to 27, we measured stiffness and intima-media thickness (IMT) of the right carotid artery and flow-mediated dilatation (FMD) of the right brachial artery.

RESULTS

Those with a VLBW had 1.1% units higher FMD (95% confidence interval [CI]: 0.0-2.2) (P = .06) and 0.5% units higher IMT relative to lumen size (95% CI: 0.1-0.9). IMT or FMD, when analyzed as the absolute change in millimeters, and carotid stiffness in the groups were similar. Among those with a VLBW, each 100-g-greater weight gain during the first 2 postnatal weeks predicted 1.1% units higher FMD (95% CI: 0.2-2.0) in adulthood.

CONCLUSIONS

Although young adults born at VLBWs, compared with those born at term, have higher levels of risk factors for cardiovascular disease, we found no clear evidence for elevated early markers of atherosclerosis. However, in relation to artery lumen diameter, IMT in the participants who had a VLBW was higher than in those who were born at term. In our study, weight gain during the first postnatal weeks had no harmful effect on the arteries in young adulthood.

Preterm birth does not affect bone mineral density in young adults

OBJECTIVE

Previous studies showed conflicting data on the effect of prematurity on bone mineral density (BMD) in infants and children. Only a few studies investigated the long-term effects of prematurity on BMD in early adulthood. The objective of our study was to assess the long-term effects of preterm birth on BMD of the total body (BMD(TB)), lumbar spine (BMD(LS)) and bone mineral apparent density of the LS (BMAD(LS)).

DESIGN

Cross-sectional study.

METHODS

It consists of two hundred and seventy-six healthy subjects without serious postnatal complications, aged 18-24 years. The contribution of gestational age to the variance in BMD in young adulthood and the differences in BMD between 151 subjects born preterm (median gestational age 32.2 weeks (interquartile range (IQR) 30.3-34.0)) and 125 subjects born at term (median gestational age 40.0 weeks (IQR 39.0-40.0)) were investigated. BMD was determined by dual-energy X-ray absorptiometry.

RESULTS

There were no significant linear correlations between gestational age and BMD(TB) (r=0.063, P=0.30), BMD(LS) (r=0.062, P=0.31) and BMAD(LS) (r=0.069, P=0.26). Also after adjustment for possible confounders, gestational age was no significant contributor to the variance in BMD(TB) (P=0.27), BMD(LS) (P=0.91) and BMAD(LS) (P=0.87). No significant differences were found between preterm and term subjects with regard to BMD(TB), BMD(LS) and BMAD(LS).

CONCLUSION

In our cohort of 276 young adults, aged 18-24 years, gestational age was not a significant determinant in the variance of BMD. Preterm birth without serious postnatal complications is not associated with a lower BMD in young adulthood.

Birth weight a negative determinant of whole body bone mineral apparent density in a group of adolescent boys

The aim of this study was to explore the relation between birth weight and bone mass in a group of adolescent boys. This study included 44 adolescent (aged 14-20yr) boys. Anthropometric characteristics (height and weight) were measured and birth weights were obtained from the obstetric records. Body composition was assessed by dual-energy X-ray absorptiometry (DXA). Bone mineral content (BMC) and bone mineral density (BMD) of the whole body (WB) and the lumbar spine (L2-L4) were also assessed by DXA. Calculations of the bone mineral apparent density (BMAD) were completed for the WB and at the lumbar spine (L2-L4). The expressions WB BMC/height and WB BMD/height were calculated to adjust for WB bone size. Birth weight was positively correlated to body weight (r=0.37; p<0.05), body mass index (r=0.38; p<0.01), body fat percentage (r=0.44; p<0.01), and negatively associated with WB BMAD (r=-0.46; p<0.01). In conclusion, this study suggests that birth weight is a positive determinant of body weight, body mass index, and body fat percent but a negative determinant of WB BMAD in adolescent boys.

Birth weight and adult bone mass: a systematic literature review

SUMMARY

This systematic literature review comprised 16 studies. The association of birth weight with bone parameters was much more evident for bone mineral content (BMC) rather than bone mineral density (BMD). This is an important finding since a reduction in BMC is strongly associated with an increased risk of fractures.

INTRODUCTION

The purpose of this study was to conduct a systematic literature review of studies that have investigated the association between birth weight (BW) and adult bone mass.

METHODS

The search included English language articles, indexed in MEDLINE, using the key words: ("birth size" OR "birth weight" OR birthweight) AND (osteoporosis OR "bone mass" OR "bone density" OR "bone mineral density" OR "bone mineral content" OR "bone area"). A methodological quality appraisal of the reviewed studies was performed.

RESULTS

Sixteen articles were reviewed. Eleven of 13 studies that measured BMC verified a positive effect of BW on this parameter, and nine even after adjustment for adult body size. Among the ten studies that found an unadjusted association between BW and BMD, two reported that the significance remained after adjustment for current body size. Interaction between prenatal and postnatal variables on the determination of adult bone mass was only tested by two studies. The results must be interpreted with caution due to the existence of few papers on the issue, as well as heterogeneous sample characteristics, investigated bone sites, and implemented analysis procedures. The aspects of methodological quality that frequently fail are as follows: representativeness of the planned and actually measured sample as well as proper adjustment for confounding.

CONCLUSION

Based on the amount of accumulated evidence, it is probable that BW have a positive association with adult BMC rather than BMD, which is an important finding for clinical and public health policies since a reduction in BMC is strongly associated with an increased fracture risk.

Adults born at very low birth weight exercise less than their peers born at term

OBJECTIVE

To study the effects of very low birth weight (VLBW, <1500 g) birth on physical activity, an important protective and modifiable factor.

STUDY DESIGN

VLBW participants (n=163) with no major disability and 188 individuals born at term (mean age, 22.3 years; range, 18.5-27.1) completed a standardized questionnaire of physical activity.

RESULTS

VLBW participants reported less leisure-time conditioning physical activity. They were 1.61-fold more likely to "not exercise much," 1.61-fold more likely to exercise infrequently (once a week or less), 2.75-fold more likely to exercise with low intensity (walking), and 3.11-fold more likely to have short exercise sessions (<30 minutes). The differences were present even in subjects with no history of bronchopulmonary dysplasia or asthma and were only slightly attenuated when adjusted for height, parental education, lean body mass, and percent body fat.

CONCLUSIONS

Unimpaired adults who were VLBW exercise less during their leisure time than adults born at term. Promoting physical activity may be particularly important in the VLBW population to counteract the risks of chronic disease in adult life.

Reduced body size and shape-related symptoms in young adults born preterm with very low birth weight: Helsinki study of very low birth weight adults

OBJECTIVE

To test the hypothesis that being born prematurely with very low birth weight (VLBW) (birth weight<or=1500 g) is associated with subphenotypes of eating disorders (dissatisfaction with body shape and pursuit of thinness) in young adulthood.

STUDY DESIGN

Preterm-born VLBW subjects (n=163) and controls (n=189) born at term completed 3 subscales of Eating Disorder Inventory-2 questionnaire (EDI): Drive for Thinness, Body Dissatisfaction, and Bulimia. Data were analyzed with multiple linear regression adjusted for confounders.

RESULTS

Among both sexes, EDI total scores were lower in VLBW subjects than in controls. The fully adjusted difference was -11.0% (95% CI, -18.4%, -2.2%) for women and -11.2% (95% CI, -20.2%, -1.3%) for men. Among women the lower scores in VLBW adults were observed in each EDI subscale. Results were similar when adjusted also for fat percentage, measured by dual-energy x-ray absorptiometry. Of the covariates, higher body mass index and higher score in Beck Depression Inventory contributed significantly to a higher EDI total score.

CONCLUSIONS

Young adults, particularly women, born prematurely with VLBW have fewer body size and shape-related symptoms and possibly lower risk for eating disorders than their term-born peers.

Adult outcome of extremely preterm infants

Survival rates for extremely preterm (<28 weeks' gestational age) infants have increased and are approaching 3 in 4 with the advent of modern perinatal and neonatal intensive care. In contrast with some children with chronic diseases such as cystic fibrosis, most survivors of extreme prematurity have no ongoing health issues. However, as a group, they do have higher rates of adverse health outcomes, and more of them will present to pediatricians over time and, ultimately, to adult physicians as they grow older. Pediatricians can aid the transition to adult health care by being aware of the nutritional, cardiovascular, respiratory, motor, cognitive, psychiatric, and functional outcomes into adulthood of survivors of extreme prematurity.

Birth weight is an independent determinant of whole body bone mineral content and bone mineral density in a group of Lebanese adolescent girls

The aim of this study was to explore the relation between birth weight and bone mass in a group of adolescent girls. This study included 40 post-menarchal adolescent (aged 13-20 years) girls. Anthropometric characteristics (height and weight) were measured and birth weights were obtained from the obstetric records. Body composition, bone mineral content (BMC) and bone mineral density (BMD) of the whole body (WB) were assessed by dual-energy X-ray absorptiometry (DXA). Calculations of the ratio BMC/height and of the bone mineral apparent density (BMAD) were completed for the WB. Birth weight was positively correlated to BMC and to the ratio BMC/height even after adjusting for weight and maturation index (years since menarche). Finally, birth weight was correlated to BMD even after adjusting for weight. In conclusion, this study suggests that birth weight is an independent determinant of whole body BMC and BMD in adolescent girls.