Clinical assessment of extremely premature infants in the delivery room is a poor predictor of survival

BACKGROUND

Some neonatologists state that at the delivery of extremely premature infants they rely on "how the baby looks" when deciding whether to initiate resuscitation. Previous studies have reported poor correlation between early clinical signs and prognosis.

OBJECTIVE

To determine if neonatologists can accurately predict survival to discharge of extremely premature infants on the basis of observations in the first minutes after birth.

METHODS

We showed videos of the resuscitation of 10 extremely premature infants (<26 weeks' gestation) to attending neonatologists and fellows from the 3 major perinatal centers in Melbourne, Australia. Antenatal information was available to the observers. A monitor visible in each video displayed the heart rate and oxygen saturation of the infant. Observers were asked to estimate the likelihood of survival to discharge for each infant at 3 time points: 20 seconds, 2 minutes, and 5 minutes after birth. The predictive ability of observers was expressed as the area (95% confidence interval [CI]) under the receiver-operating-characteristic curve.

RESULTS

Seventeen attending neonatologists and 17 neonatal fellows completed the study. Receiver-operating-characteristic curves were generated for the combined and individual groups. Observers' ability to predict survival was poor (combined results): 0.61 (95% CI: 0.54-0.67) at 20 seconds, 0.59 (95% CI: 0.52-0.64) at 2 minutes, and 0.61 (95% CI: 0.55-0.67) at 5 minutes. Level of experience did not affect the observers' accuracy of predicting survival.

CONCLUSION

Neonatologists' reliance on initial appearance and early response to resuscitation in predicting survival for extremely premature infants is misplaced.

Is bedtime supper necessary for older children with diabetes using glargine insulin in multiple daily injection regimens?

AIMS

Current guidelines for dietary management of Type 1 diabetes in children recommend a carbohydrate supper before bed. However, with the introduction of insulin analogues such as glargine (with a basal insulin profile), supper may be unnecessary. The purpose of this study was to investigate whether supper is required to prevent nocturnal hypoglycaemia when using multiple daily injections, with glargine as the basal insulin and rapid-acting insulin pre-meals, in older children with Type 1 diabetes.

METHODS

Thirty-five children aged 10-18 years with Type 1 diabetes were recruited to a randomized cross-over trial (supper vs. no supper). Each phase consisted of three consecutive days of wearing a continuous glucose-monitoring system (CGMS) to record nocturnal blood glucose levels in the home setting. The supper phase included one 15-g carbohydrate dairy snack consumed before bed. The evening meals were standardized. Activity was restricted.

RESULTS

Valid CGMS data were obtained for 163 nights (85 supper, 78 no supper). Nocturnal hypoglycaemia rates were similar in the supper and no-supper groups (32.9% vs. 33.3% of nights; P = 0.96).

CONCLUSIONS

This study suggests that supper is not necessary for all children to prevent nocturnal hypoglycaemia when using glargine insulin. The recommendation for inclusion of supper should be individually tailored and not mandatory.

Measuring glycaemic variation

The measurement of glycaemic variation (GV) is conceived to be of clinical significance in determining diabetes outcomes. The debate as to the importance of GV has been complicated by studies using various metrics of GV in qualitatively different datasets. The purpose of this review is to discuss the properties of 8 of the more commonly used metrics (M-value, MAGE, "J"-index, CONGA, BG rate of change, ADRR, Lability/HYPO score and GRADE). Comparable metrics that can be used to measure continuous glycaemic measurements (CGM) (SDBGL, "J"-index, MAGE, CONGA, GRADE) were then compared in assessing diabetic and non-diabetic datasets. In non-diabetic conditions there was very close correlation (correlation coefficients >0.92) between SDBGL, MAGE and CONGA, however under diabetic conditions the correlation coefficients of the GV metrics diminished significantly. The varying GV metrics have varying inherent properties depending upon the purpose for which they were designed and should not be seen as being interchangeable. Investigators therefore need to be clear about the nature of their enquiry of GV and choose an appropriate metric.

Quality of care at the end of life in children with cancer

AIM

Current Australian guidelines for the provision of paediatric palliative care highlight the importance of services being focused on the needs of the child and family. We aimed to establish parents' level of satisfaction with the quality of care currently being provided to children dying of cancer.

METHODS

We interviewed 96 parents of children who died of cancer in Melbourne, Australia between 1996 and 2004 to ascertain how they rated the care provided to their child during the end-of-life period.

RESULTS

A majority of parents were satisfied with the care provided by their primary oncologist, local doctors, palliative care services and home-care nurses. Most parents felt that discussions about key medical and treatment decisions were appropriate and clearly understood. Parents were generally satisfied with the leadership roles undertaken in decision-making in the end-of-life period; however, parents who were not satisfied indicated that they would like additional involvement of their primary oncologist.

CONCLUSIONS

Current approaches to end-of-life care in children with cancer appear to be satisfactory. The main focus should continue to be on open and honest communication.

Oxygen saturation and heart rate during delivery room resuscitation of infants <30 weeks' gestation with air or 100% oxygen

BACKGROUND

Because of concerns about harmful effects of 100% oxygen on newborn infants, air has started to be used for resuscitation in the delivery room.

OBJECTIVE

To describe changes in preductal oxygen saturation (Spo(2)) and heart rate (HR) in the first 10 min after birth in very preterm infants initially resuscitated with 100% oxygen (OX(100)) or air (OX(21)).

PATIENTS AND METHODS

In July 2006, policy changed from using 100% oxygen to air. Observations of Spo(2) and HR before and after the change were recorded whenever a member of the research team was available to attend the birth.

RESULTS

There were 20 infants in the OX(100) group and 106 in the OX(21) group. In the OX(100) group, Spo(2) had risen to a median of 84% after 2 min and 94% by 5 min. In the OX(21) group, median Spo(2) was 31% at 2 min and 54% at 5 min. In the OX(21) group, 92% received supplemental oxygen at a median of 5 min; the Spo(2) rose to a median of 81% by 6 min. In the first 10 min after birth, 80% and 55% of infants in the OX(100) and OX(21) groups, respectively, had an Spo(2) > or =95%. Increases in HR over the first 10 min were very similar in the two groups.

CONCLUSIONS

Most very preterm infants received supplemental oxygen if air was used for the initial resuscitation. In these infants, the use of backup 100% oxygen and titration against Spo(2) resulted in a similar course to "normal" term and preterm infants. Of the infants resuscitated with 100% oxygen, 80% had Spo(2) > or =95% during the first 10 min. The HR changes in the two groups were very similar.

Effect of gestation on initiation and duration of breastfeeding

OBJECTIVE

The aim of this study was to investigate the effect of gestation on initiation and duration of breastfeeding in Australian infants.

METHODS

The Longitudinal Study of Australian Children recruited a national sample of children born between March 2003 and February 2004 (n = 3600 in this multivariate sample).

RESULTS

Breastfeeding initiation was lower for infants of 35-36 weeks' gestation (88.2%) than 37-39 weeks' gestation (92.0%) and > or =40 weeks' gestation (93.9%). At 6 months, 41.2% of infants 35-36 weeks' gestation were breastfeeding compared with 54.5% of 37-39 weeks' gestation infants and 60.5% of infants born > or =40 weeks. Compared with infants born > or =40 weeks, infants born at 35-36 weeks had an adjusted odds ratio (OR) of 0.51 (95% CI 0.34 to 0.76) and infants born at 37-39 weeks had an adjusted OR of 0.80 (95% CI 0.69 to 0.93) of breastfeeding at 6 months.

CONCLUSION

Infants born before 40 weeks are at greater risk of being artificially fed than infants born > or =40 weeks.

Socioeconomic status and rates of breastfeeding in Australia: evidence from three recent national health surveys

OBJECTIVE

To investigate whether the relationship between socioeconomic status and breastfeeding initiation and duration changed in Australia between 1995 and 2004.

DESIGN AND SETTING

Secondary analysis of data from national health surveys (NHSs) conducted by the Australian Bureau of Statistics in 1995, 2001 and 2004-05. The Socio-Economic Indexes for Areas (SEIFA) classification was used as a measure of socioeconomic status.

MAIN OUTCOME MEASURES

Rates of initiation of breastfeeding; rates of breastfeeding at 3, 6 and 12 months.

RESULTS

Between the 1995 and 2004-05 NHSs, there was little change in overall rates of breastfeeding initiation and duration. In 2004-05, breastfeeding initiation was 87.8%, and the proportions of infants breastfeeding at 3, 6 and 12 months were 64.4%, 50.4% and 23.3%, respectively. In 1995, the odds ratio (OR) of breastfeeding at 6 months increased by an average of 13% (OR, 1.13 [95% CI, 1.07-1.19]) for each increase in SEIFA quintile; in 2001, the comparative increase was 21% (OR, 1.21 [95% CI, 1.12-1.30]); while in 2004-05, the comparative increase was 26% (OR, 1.26 [95% CI, 1.17-1.36]). Breastfeeding at 3 months and 1 year showed similar changes in ORs. There was little change in the ORs for breastfeeding initiation.

CONCLUSION

Although overall duration of breastfeeding remained fairly constant in Australia between 1995 and 2004-05, the gap between the most disadvantaged and least disadvantaged families has widened considerably over this period.

Maternal obesity and initiation and duration of breastfeeding: data from the longitudinal study of Australian children

The aim of this paper is to investigate whether the lower rate of breastfeeding at 6 months by overweight and obese mothers is primarily due to these women giving up breastfeeding in the first week postpartum using a cross-sectional population survey. The sample is children from the infant cohort (about 12 months of age) of Wave 1 (2004) of the Longitudinal Study of Australian Children for whom breastfeeding and maternal information were available (n = 3075). Definitions used: normal-weight body mass index (BMI, kg/m(2)) 20 to <25, overweight BMI 25 to <30, obese BMI > or =30. Breastfeeding initiation was 95.1% for normal-weight women, 92.8% for overweight women and 87.1% for obese women. At 6 months, 64% of normal-weight women were breastfeeding, compared with 54% of overweight and 44% of obese women. On multivariate analysis, for women who initiated breastfeeding, overweight women had an odds ratio (OR) of 1.52 [95% confidence interval (CI) 1.02, 2.28] and obese women had an OR of 2.54 (95% CI 1.70, 3.79) of stopping breastfeeding by 1 week compared with normal-weight women (adjusted for maternal age, education, smoking, level of socio-economic disadvantage, caesarean birth, admission to special care nursery). For women who breastfed for at least 1 week, overweight women had an adjusted OR of 1.26 (1.04, 1.53) and obese women had an adjusted OR of 1.38 (1.10, 1.73) of ceasing to breastfeed before 6 months, compared with normal-weight women. In conclusion, among overweight/obese women who initiate breastfeeding, higher rates of cessation of breastfeeding in both the immediate postpartum period and in the first 6 months contribute to the shorter duration.

Twice-daily variable insulin regimens: proportions of insulin types have little impact on glycaemic control in primary school-aged children

AIM

To ascertain the relationship between glycaemic outcome and proportions and timing of insulin admixture in a cohort of primary school-aged children who were receiving insulin in a twice-daily regimen.

METHODS

Children aged 4-10 years with Type 1 diabetes of > 2 years duration and on twice-daily variable insulin regimens were eligible for inclusion in this study, which took place over a 12-month period. Characteristics of insulin regimen [total daily dose (TDD), proportion of total daily dose given in the morning and proportion of the TDD given as intermediate-acting insulin] were compared with parameters of glycaemia including glycated haemoglobin (HbA(1c)) and continuous glucose monitoring measures (mean glucose, per cent time in various glycaemic ranges, and intra- and inter-day glycaemic variation).

RESULTS

Forty-nine children completed the study. Participants were all prepubertal at the start of the study and representative of the local diabetes population aged 4-10 years (mean age 8.2 years, mean duration of diabetes 3.5 years, mean HbA(1c) 8.1%). The mean TDD was 0.9 units/kg/day (range 0.6-1.3). The TDD, percentage of TDD given as intermediate-acting insulin and the percentage of TDD given as the morning dose were not associated with HbA(1c), mean continuous glucose monitoring system glucose, per cent time in various glycaemic ranges or intra- and inter-day glycaemic variation.

CONCLUSIONS

Insulin proportions in twice-daily, variable insulin regimens are not associated with any short- or medium-term glycaemic outcomes.

Optimizing postprandial glycemia in pediatric patients with type 1 diabetes using insulin pump therapy: impact of glycemic index and prandial bolus type

OBJECTIVE

Postprandial glycemic excursions may contribute to the development of diabetes-related complications. Meals of high and low glycemic index (GI) have distinct effects on postprandial glycemia (PPG). Insulin pump therapy offers the potential to tailor insulin delivery to meal composition; however, optimal bolus types for meals of different glycemic loads have not been defined. We sought to compare the impact of GI combined with varying prandial bolus types on PPG.

RESEARCH DESIGN AND METHODS

An open crossover study examining the effects of four different meal and bolus-type combinations on 3-h PPG (measured by continuous glucose-monitoring system [CGMS]) was conducted. A total of 20 young people aged 8-18 years with type 1 diabetes using insulin-pump therapy participated. Meals had equal macronutrient, energy, and fiber content and differed only in GI (low vs. high). Participants consumed meals of the same GI on consecutive days and were randomized to receive either a standard (100%) or a dual-wave (DW) (50:50% over 2 h) bolus each day. CGMS data from 10 healthy control participants established the target response to each meal.

RESULTS

A DW bolus before low-GI meals decreased PPG area under the curve (AUC) by up to 47% (P = 0.004) and lowered the risk of hypoglycemia for the same premeal glucose (P = 0.005) compared with standard bolus. High-GI meals resulted in significant upward PPG excursions with greater AUC (P = 0.45), regardless of bolus type.

CONCLUSIONS

These data support the use of a DW bolus with low GI meals to optimize PPG in patients with type 1 diabetes using insulin pump therapy.

Accuracy of pulse oximetry measurement of heart rate of newborn infants in the delivery room

OBJECTIVE

To determine the accuracy of heart rate obtained by pulse oximetry (HR(PO)) relative to HR obtained by 3-lead electrocardiography (HR(ECG)) in newborn infants in the delivery room.

STUDY DESIGN

Immediately after birth, a preductal PO sensor and ECG leads were applied. PO and ECG monitor displays were recorded by a video camera. Two investigators reviewed the videos. Every two seconds, 1 of the investigators recorded HR(PO) and indicators of signal quality from the oximeter while masked to ECG, whereas the other recorded HR(ECG) and ECG signal quality while masked to PO. HR(PO) and HR(ECG) measurements were compared using Bland-Altman analysis.

RESULTS

We attended 92 deliveries; 37 infants were excluded due to equipment malfunction. The 55 infants studied had a mean (+/-standard deviation [SD]) gestational age of 35 (+/-3.7) weeks, and birth weight 2399 (+/-869) g. In total, we analyzed 5877 data pairs. The mean difference (+/-2 SD) between HR(ECG) and HR(PO) was -2 (+/-26) beats per minute (bpm) overall and -0.5 (+/-16) bpm in those infants who received positive-pressure ventilation and/or cardiac massage. The sensitivity and specificity of PO for detecting HR(ECG) <100 bpm was 89% and 99%, respectively.

CONCLUSION

PO provided an accurate display of newborn infants' HR in the delivery room, including those infants receiving advanced resuscitation.

Accuracy of pulse oximetry in assessing heart rate of infants in the neonatal intensive care unit

AIM

To determine the accuracy of pulse oximetry measurement of heart rate in the neonatal intensive care unit.

METHODS

Stable preterm infants were monitored with a pulse oximeter and an ECG. The displays of both monitors were captured on video. Heart rate data from both monitors, including measures of signal quality, were extracted and analysed using Bland Altman plots.

RESULTS

In 30 infants the mean (SD) difference between heart rate measured by pulse oximetry and electrocardiography was -0.4 (12) beats per minute. Accuracy was maintained when the signal quality or perfusion was low.

CONCLUSION

Pulse oximetry may provide a useful measurement of heart rate in the neonatal intensive care unit. Studies of this technique in the delivery room are indicated.

Maternal employment and breastfeeding: results from the longitudinal study of Australian children

AIM

To investigate the effect of maternal postnatal employment on breastfeeding duration in Australia in the first 6 months after birth.

METHOD

Secondary data analysis of the infant data (2004) from the Longitudinal Study of Australian Children (LSAC). Complete maternal and breastfeeding data were available for 3,697 infants. Multivariable logistic regression was used to investigate the effect of timing of resumption of maternal employment and maternal employment status on breastfeeding at 6 months postpartum after adjustment for maternal education, maternal age, maternal smoking during pregnancy and socioeconomic status of the child's area of residence.

RESULTS

Fewer women employed full-time were breastfeeding their infants at 6 months (39%) than nonemployed women (56%). Participation in full-time employment before 6 months had a strong, negative effect on the likelihood of continuing breastfeeding for 6 months, adjusted OR = 0.35 (95%CI: 0.22-0.55). Compared to nonemployed women, fewer women in part-time employment were breastfeeding at 6 months (44%), adjusted OR = 0.49 (95% CI: 0.37-0.64).

CONCLUSIONS

Results from this large representative cohort of Australian infants confirm that maternal employment in the first 6 months of life contributes to premature cessation of breastfeeding even when known risk factors for breastfeeding cessation are controlled for.

Breastfeeding and the introduction of solids in Australian infants: data from the 2001 National Health Survey

OBJECTIVE

To present estimates on rates of breastfeeding and timing of introduction of solid foods to Australian children, 1998-2001.

METHODS

Analysis of data from the 2001 Australian National Health Survey (NHS) using lifetable methods. Infant feeding questions were asked by personal interview in respect to 1,883 children aged under three years of age.

RESULTS

At discharge from hospital, 83.3% of infants were breastfeeding, which is similar to estimates from the 1995 NHS. At 13 weeks postpartum, 64.3% were breastfeeding, 49.0% at 25 weeks and 24.9% were continuing to breastfeed at one year. At 25 weeks, 18.4% of infants were fully breastfed. Solid food was being offered regularly to 15.2% of infants at 13 weeks and 88.0% by 26 weeks.

CONCLUSION

Fewer than 50% of infants are receiving breast milk at six months, which is considerably lower than the 80% figure recommended by the latest Dietary Guidelines for Children and Adolescents. Very few Australian infants are being exclusively breastfed for the recommended six months. Infant feeding practices in Australia appear to have remained unchanged between 1995 and 2001.

Hyperglycemia and externalizing behavior in children with type 1 diabetes

OBJECTIVE

Ancedotally, parents report behavioral changes in their diabetic children who have fluctuating blood glucose levels. This study aimed to test associations between intercurrent glycemia and child behavior in an ambulant setting.

RESEARCH DESIGN AND METHODS

Prepubertal children attending the Royal Children's Hospital, Melbourne, Australia, with type 1 diabetes received glycemic assessment and simultaneous behavioral assessment on two occasions 6 months apart. Subjects wore a continuous glucose monitor over a 72-h period, and parents completed the Behavior Assessment System for Children at the two study time points.

RESULTS

There was a high correlation between intra-individual externalizing and internalizing behavior scores (r = 0.88, P < 0.001 and r = 0.81, P < 0.001, respectively) at the two time points. Mean blood glucose (MBG) was significantly associated with the mean externalizing behavior score (beta = 1.7 [95% CI 0.6-2.8], adjusted r(2) = 0.088). Percentage of time in the normal (r = -0.2 [-0.3 to -0.5], adjusted r(2) = 0.068) and high (r = 0.2 [0.07-0.3], adjusted r(2) = 0.089) glycemic ranges were significantly associated with the mean externalizing behavior score. For every 5% increase in time in the normal glycemic range, there was a decrease in the externalizing behavior score of 1.0, and for every 5% increase in time in the high glycemic range there was an increase in the externalizing behavior score of 1.0. There was no significant association between MBG and the mean internalizing behavior score.

CONCLUSIONS

Externalizing behaviors were associated with intercurrent glycemic status. These findings underscore the importance of understanding the mechanisms of this association and how it might impact ultimate diabetes outcomes.

Marked increase in type 1 diabetes mellitus incidence in children aged 0-14 yr in Victoria, Australia, from 1999 to 2002

OBJECTIVES

The objectives of the study were to (i) determine the incidence of type 1 diabetes mellitus (T1DM) in children aged <15 yr in Victoria, Australia, from 1999 to 2002 and (ii) to analyze trends in incidence over this period.

METHODS

Prospective population-based incidence study. The primary source of case ascertainment was from the Australasian Paediatric Endocrine Group (APEG) Victorian diabetes register. The secondary source was the National Diabetes Register (NDR), which ascertains cases from the National Diabetes Service Scheme (NDSS), a Commonwealth government initiative, where patients register to receive diabetes supplies at a subsidized price.

MAIN OUTCOME MEASURES

Age-standardized incidence, trends in incidence by age, sex and year, and variation in incidence by region, season, and socioeconomic status.

RESULTS

Case ascertainment was 99.1% complete using the capture-recapture method. The mean annual age-standardized incidence was 19.3 per 100 000 person years from 1999 to 2002. On average, incidence increased by 9.3% per year, with a greater relative increase in the 0-4 yr age-group (p = 0.037). No gender bias in incidence was found, but the increase in females was statistically significant (13.6% per year, 95% confidence interval 3.7-24.3). Variation in geographical distribution and seasonal onset of incidence was not statistically significant.

CONCLUSIONS

The marked increase in the incidence of T1DM in Victoria is greater than that recently described in other Australia states and developed nations. The etiology of this rise is unclear, while the increased caseload has major implications for diabetes health care providers for current and future resource allocation.

Social consumption of alcohol in adolescents with Type 1 diabetes is associated with increased glucose lability, but not hypoglycaemia

AIM

To determine the effects of social consumption of alcohol by diabetic adolescents on glycaemic control.

METHODS

Fourteen (five male) patients aged > 16 years were recruited from the diabetes clinic at the Royal Children's Hospital. The continuous glucose monitoring system (CGMS) was attached at a weekend when alcohol consumption was planned for one night only. For each patient, the 12-h period from 18.00 h to 06.00 h for the night with alcohol consumption (study period) was compared with the same period with non-alcohol consumption (control period) either 24 h before or after the alcohol study night. Thus, each subject was his/her own control. Glycaemic outcomes calculated from continuous glucose monitoring included mean blood glucose (MBG), percentage of time spent at low glucose levels (CGMS < 4.0 mmol/l), normal glucose levels (CGMS 4.0-10.0 mmol/l) and high glucose levels (> 10.0 mmol/l) and continuous overall net glycaemic action (CONGA).

RESULTS

The mean number of standard alcohol drinks consumed during the study period was 9.0 for males and 6.3 for females. There was no difference in percentage of time at high and normal glucose levels in the study and control periods. During the control period, there was a higher percentage of time with low glucose levels compared with the study period (P < 0.05). There was an increased level of glycaemic variation during the study time when compared with the control period.

CONCLUSIONS

In an uncontrolled, social context, moderately heavy alcohol consumption by adolescents with Type 1 diabetes appears to be associated with increased glycaemic variation, but not with low glucose levels.

Reliability of the hazelbaker assessment tool for lingual frenulum function

Background

About 3% of infants are born with a tongue-tie which may lead to breastfeeding problems such as ineffective latch, painful attachment or poor weight gain. The Hazelbaker Assessment Tool for Lingual Frenulum Function (HATLFF) has been developed to give a quantitative assessment of the tongue-tie and recommendation about frenotomy (release of the frenulum). The aim of this study was to assess the inter-rater reliability of the HATLFF.

Methods

Fifty-eight infants referred to the Breastfeeding Education and Support Services (BESS) at The Royal Women's Hospital for assessment of tongue-tie and 25 control infants were assessed by two clinicians independently.

Results

The Appearance items received kappas between about 0.4 to 0.6, which represents "moderate" reliability. The first three Function items (lateralization, lift and extension of tongue) had kappa values over 0.65 which indicates "substantial" agreement. The four Function items relating to infant sucking (spread, cupping, peristalsis and snapback) received low kappa values with insignificant p values. There was 96% agreement between the two assessors on the recommendation for frenotomy (kappa 0.92, excellent agreement). The study found that the Function Score can be more simply assessed using only the first three function items (ie not scoring the sucking items), with a cut-off of ≤4 for recommendation of frenotomy.

Conclusion

We found that the HATLFF has a high reliability in a study of infants with tongue-tie and control infants

How to calculate standard errors for population estimates based on Australian National Health Survey data

The National Health Surveys (NHS), conducted regularly by the Australian Bureau of Statistics, are designed to obtain benchmark information on a range of health-related issues and to enable the monitoring of health trends over time. Confidentialised Unit Record Files (CURFs), containing detailed individual-level NHS data, are available from the ABS. When using the CURF data to make an estimate relating to the Australian population, the precision of the estimate should also be calculated, but due to the complexity of the survey design and the limited survey design information in the CURF, this is not straightforward. This paper explains three different methods for calculating standard errors for population estimates obtained using CURF data: (i) using the estimates of relative standard errors published by the ABS; (ii) using the replicate weights provided by the ABS in the CURF; and (iii) assuming the survey design is a simple random sample. The most appropriate method will depend on which survey is being analysed and the type of population estimate; this is discussed in detail. Worked examples for each method using data from the 2001 NHS CURF are provided, together with Stata 9 code illustrating the implementation of each method.

A novel approach to continuous glucose analysis utilizing glycemic variation

BACKGROUND

Various methodologies have been proposed for analysis of continuous glucose measurements. These methods have mainly focused on the proportion of low or high glucose readings and have not attempted to analyze other dimensions of the data obtained. This study proposes an algorithm for analysis of continuous glucose data including a novel method of assessing glycemic variability.

METHODS

Mean blood glucose and mean of daily differences (MODD) assessed the degree that the Continuous Glucose Monitoring System (CGMS, Medtronic MiniMed, Northridge, CA) trace was representative of the 3-month glycemic pattern. Percentages of times in low, normal, and high glucose ranges were used to assess marked glycemic excursion. Continuous overall net glycemic action (CONGA), a novel method developed by the authors, assessed intra-day glycemic variability. These methods were applied to 10 CGMS traces chosen randomly from those completed by children with type 1 diabetes from the Royal Children's Hospital, Melbourne, Victoria, Australia and 10 traces recorded by healthy volunteer controls.

RESULTS

The healthy controls had lower values for mean blood glucose, MODD, and CONGA. Patients with diabetes had higher percentages of time spent in high and low glucose ranges. There was no overlap between the CONGA values for patients with diabetes and for controls, and the difference between controls and patients with diabetes increased markedly as the CONGA time period increased.

CONCLUSIONS

We advocate an approach to the analysis of CGMS data based upon a hierarchy of relevant clinical questions alluding to the representative nature of the data, the amount of time spent in glycemic excursions, and the degree of glycemic variation. Integrated use of these algorithms distinguishes between various patterns of glycemic control in those with and without diabetes.

The relationship between maternal smoking and breastfeeding duration after adjustment for maternal infant feeding intention

AIM

To investigate whether maternal smoking remains associated with decreased breastfeeding duration after adjustment for the mother's infant feeding intention.

METHOD

Pregnant women resident within Avon, UK, expected to give birth between 1 April 1991 and 31 December 1992 were recruited in a longitudinal cohort study. Main outcome measures included maternal infant feeding intention at 32 wk of pregnancy: intention for the first week, intention for the rest of the first month and intention in months 2 to 4. Maternal smoking was defined as any smoking reported at any time during pregnancy. Data on initiation and duration of breastfeeding were based on the questionnaire at 6 mo postpartum, supplemented by data from the 15-mo questionnaire if necessary.

RESULTS

Women who smoked during pregnancy had an adjusted odds ratio of 1.5 (95% CI: 1.3-1.7) of not breastfeeding at 6 mo compared to non-smokers (adjusting for maternal age, education and intention). Survival analysis of duration of breastfeeding in the first 6 mo postpartum found that women who intended to breastfeed for less than 1 mo were 78% more likely to stop at any given time than women planning to breastfeed for at least 4 mo, while smokers were 17% more likely to stop breastfeeding than non-smokers.

CONCLUSION

Although women who smoke are less likely to breastfeed their infants than are non-smoking women, it appears that this is largely due to lower motivation to breastfeed rather than a physiological effect of smoking on their milk supply.

Relationship between prenatal infant feeding intention and initiation and duration of breastfeeding: a cohort study

AIM

To report the relationship between maternal prenatal intention to breastfeed and the actual initiation and duration of breastfeeding.

METHODS

Pregnant women resident within Avon, UK, expected to give birth between 1 April 1991 and 31 December 1992 were recruited in a longitudinal cohort study. Main outcome measures included maternal infant feeding intention (breastfeed, breast and bottle feed, bottle feed, or uncertain) at 32 wk of pregnancy: intention in the first week, intention for the rest of the first month and intention in months 2 to 4; initiation and duration of breastfeeding up to six months.

RESULTS

Data were available on 10,548 women. Prenatal intention to breastfeed had an influence on both initiation and duration of breastfeeding. Of the women intending to bottle feed from birth, only 3.4% initiated breastfeeding compared with 96.6% of women planning to breastfeed for at least four months. At six months postpartum, the mean duration of breastfeeding for women intending to breastfeed for at least five months was 4.4 mo (95% CI 4.3, 4.4), compared with 2.5 mo (95% CI 2.4, 2.6) for women with a prenatal intention to breastfeed for only one month. Logistic regression, using intended duration as the only explanatory variable, correctly predicted 91.4% of breastfeeding initiation and 72.2% of infant feeding at six months.

CONCLUSIONS

This large population-based study confirms the strength of the relationship between maternal prenatal intention to breastfeed and both breastfeeding initiation and duration. Maternal intention was a stronger predictor than the standard demographic factors combined. This should be taken into account in future research, and trials should be undertaken to establish whether interventions could alter maternal intention and thereby increase rates of breastfeeding initiation and duration.

Does maternal smoking have a negative physiological effect on breastfeeding? The epidemiological evidence

Women who smoke are less likely to breastfeed their children than nonsmokers. It is thought that nicotine has a negative effect on breastmilk supply by suppressing prolactin levels. The aim of this review was to assess the epidemiological evidence that maternal smoking has a negative physiological effect on breastfeeding. The following data sources were searched: The Cochrane Library, Medline, CINAHL, Current Contents, Psychinfo, Sociological Abstracts and the Lactation Resource Centre (Australian Breastfeeding Association) using the key words 'smoking' and 'breastfeeding' or 'infant feeding'. The Journal of Human Lactation and Birth were hand searched. Women who smoke are less likely to intend to breastfeed, less likely to initiate breastfeeding, and likely to breastfeed for a shorter duration than nonsmokers. Several studies have found a dose-response relationship between the number of cigarettes smoked each day and breastfeeding intention, initiation, and duration that persists after adjusting for confounding factors. In some population groups a high proportion of smokers breastfeed successfully. The association between maternal smoking and lack of breastfeeding is consistent across different study designs in a range of countries. Given that women who smoke are less likely to intend to breastfeed, however, it cannot be assumed that the relationship between smoking and duration of breastfeeding is a physiological one. If smoking had a consistent negative physiological effect on lactation, one would not expect to see such wide variations in breastfeeding rates among women who smoke. Therefore, it is likely that psychosocial factors are largely responsible for the lower rates of breastfeeding found in women who smoke compared with those who do not.

The introduction of breast milk substitutes and solid foods: evidence from the 1995 National Health Survey

OBJECTIVE

To report the introduction of breast milk substitutes and solid foods to Australian children between 1992 and 1995.

METHODOLOGY

Analysis of data from the 1995 Australian National Health Survey. Infant feeding questions were asked by personal interview in respect to 3,252 children aged under four years of age.

RESULTS

By the age of 26 weeks, the majority of children had been given infant formula (56.9%) and solid food (61.5%). More than one-quarter (27.1%) of children received cow's milk regularly during the first 12 months. Only 7% of children were given solids in the first 12 weeks of life. Soy milk was given to 14.2% of children aged less than four years.

CONCLUSION

The majority of children in Australia are not being exclusively breastfed for six months as recommended by the World Health Organization (WHO). The intake of cow's milk before 12 months of age and the timing of introduction of solids needs to be monitored. Future surveys should collect more detail about type of infant formula so that the proportion of infants receiving soy-based formula and other formula can be assessed.

Does maternal smoking have a negative physiological effect on breastfeeding? The epidemiological evidence

BACKGROUND

Women who smoke are less likely to breastfeed their children than nonsmokers. It is thought that nicotine has a negative effect on breastmilk supply by suppressing prolactin levels. The aim of this review was to assess the epidemiological evidence that maternal smoking has a negative physiological effect on breastfeeding.

METHODS

The following data sources were searched: The Cochrane Library, Medline, CINAHL, Current Contents, Psychinfo, Sociological Abstracts and the Lactation Resource Centre (Australian Breastfeeding Association) using the key words "smoking" and "breastfeeding" or "infant feeding." The Journal of Human Lactation and Birth were hand searched.

RESULTS

Women who smoke are less likely to intend to breastfeed, less likely to initiate breastfeeding, and likely to breastfeed for a shorter duration than nonsmokers. Several studies have found a dose-response relationship between the number of cigarettes smoked each day and breastfeeding intention, initiation, and duration that persists after adjusting for confounding factors. In some population groups a high proportion of smokers breastfeed successfully.

CONCLUSIONS

The association between maternal smoking and lack of breastfeeding is consistent across different study designs in a range of countries. Given that women who smoke are less likely to intend to breastfeed, however, it cannot be assumed that the relationship between smoking and duration of breastfeeding is a physiological one. If smoking had a consistent negative physiological effect on lactation, one would not expect to see such wide variations in breastfeeding rates among women who smoke. Therefore, it is likely that psychosocial factors are largely responsible for the lower rates of breastfeeding found in women who smoke compared with those who do not.

Does maternal obesity adversely affect breastfeeding initiation and duration?

OBJECTIVE

To examine the relationship between maternal obesity and the initiation and duration of breastfeeding.

METHODS

Analysis was made of the 1995 National Health Survey, in which personal interviews were conducted on a multistage area sample of private dwellings and a list sample of non-private dwellings in all States and Territories of Australia. Mothers between the ages of 17 and 50 years (n = 1991) with children under the age of four years in 1995 participated in the study.

RESULTS

Of the group of mothers with a body mass index (BMI) of 20-25, 89.2% (95% confidence interval (CI) 87.4-91.0) initiated breastfeeding, compared with 82.3% (95% CI 77.6-87.0) of mothers with a BMI of 30 or more. There was also a significant difference between the mean and median duration of breastfeeding of obese and non-obese mothers (BMI 30 and over, < 25, respectively). These differences remained significant when maternal smoking, age and other sociodemographic factors were taken into consideration.

CONCLUSIONS

Health professionals should be aware that obese women may be at increased risk of not breastfeeding or stopping breastfeeding prematurely.

Does maternal obesity adversely affect breastfeeding initiation and duration?

OBJECTIVE

To examine the relationship between maternal obesity and the initiation and duration of breastfeeding.

METHODS

Analysis was made of the 1995 National Health Survey, in which personal interviews were conducted on a multistage area sample of private dwellings and a list sample of non-private dwellings in all states and territories of Australia. Mothers between the ages of 17 and 50 years (n = 1991) with children under the age of 4 years in 1995 participated in the study.

RESULTS

Of the group of mothers with a body mass index (BMI) of 20-25, 89.2% (95% confidence interval (CI) 87.4-91.0) initiated breastfeeding, compared with 82.3% (95% CI 77.6-87.0) of mothers with a BMI of 30 or more. There was also a significant difference between the mean and median duration of breastfeeding of obese and non-obese mothers (BMI 30 and over, < 25, respectively). These differences remained significant when maternal smoking, age and other sociodemographic factors were taken into consideration.

CONCLUSIONS

Health professionals should be aware that obese women may be at increased risk of not breastfeeding or stopping breastfeeding prematurely.

Who's overweight? Comparison of the medical definition and community views

OBJECTIVE

To investigate the extent to which people who are medically defined as overweight perceive themselves to be overweight.

DESIGN

Secondary data analysis of the National Health Survey and the National Nutrition Survey conducted by the Australian Bureau of Statistics in 1995.

PARTICIPANTS

10,652 people aged 18 years and over (5076 men, 5576 women) in a multistage cluster sample of households throughout Australia.

MAIN OUTCOME MEASURES

Body mass index (BMI) based on measured height and weight; self-reported perception of body weight (underweight, acceptable weight, or overweight).

RESULTS

Among people with a measured BMI > or = 25, 49.3% of men (95% CI, 48.1%-50.5%) and 72.0% of women (95% CI, 70.8%-73.1%) considered themselves overweight. Among those with a measured BMI < 25, 3.4% of men (95% CI, 2.8%-4.1%) and 12.4% of women (95% CI, 11.4%-13.3%) considered themselves overweight. Older women were less likely to perceive themselves as overweight than younger women. The lowest BMI at which at least half the respondents considered themselves overweight was 26 to < 27 for women aged 18-59 years, and 28 to < 29 for older women and men.

CONCLUSION

For many people, particularly men and older women, the meaning of "overweight" differs from the medical definition. Clinical and public health weight reduction programs which do not take this into account are unlikely to be successful.