Pain Control in a Randomized, Controlled, Clinical Trial Comparing Moist Exposed Burn Ointment and Conventional Methods in Patients With Partial-Thickness Burns

Conventional management of partial-thickness burn wounds includes the use of paraffin gauze dressing, frequently with topical silver-based antibacterial creams. Some creams form an overlying slough that renders wound assessment difficult and are painful upon application. An alternative to conventional management, moist exposed burn ointment (MEBO), has been proposed as a topical agent that may accelerate wound healing and have antibacterial and analgesic properties. One hundred fifteen patients with partial-thickness burns were randomly assigned to conventional (n = 58) or MEBO treatment (n = 57). A verbal numerical rating score of pain was made in the morning, after burn dressing, and some 8 hours later. Patient pain profiles were summarized by locally weighted regression smoothing technique curves and the difference between treatments estimated using multilevel regression techniques. Mean verbal numerical rating scale pain levels (cm) in week 1 for all patients were highest at 3.2 for the after dressing assessment, lowest in the evening at 2.6, and intermediate in the morning at 3.0. This pattern continued at similar levels in week 2 and then declined by a mean of 0.5 in all groups in week 3. There was little evidence to suggest a difference in pain levels by treatment group with the exception of the postdressing pain levels in the first week when those receiving MEBO had a mean level of 0.7 cm (95% confidence interval, 0.2 to 1.1) lower than those on conventional therapy. MEBO appeared to bring greater pain relief for the postdressing assessment during the first week after burns. This initial relief, together with comparable pain levels experienced on other occasions, indicates that MEBO could be an alternative to conventional burns management.

Measuring quality of life in Chinese cancer patients: a new version of the Functional Living Index for Cancer (Chinese)

INTRODUCTION

Since its translation into Chinese, the Functional Living Index for Cancer (FLIC) has not been widely received due to some of its difficulties. We modified its visual analogue scale (VAS) to an ordered categorical scale and changed some of the wording in the instrument. This study examined the measurement properties of the modified FLIC.

MATERIALS AND METHODS

The modified version of FLIC and the Functional Assessment of Cancer Therapy (FACT-G Chinese version 4) were filled in by 140 patients recruited from the National Cancer Centre Singapore. The patients' FLIC scores were compared with their clinical characteristics to establish known-group validity. Convergent and divergent validity of FLIC were examined by correlation analysis with FACT-G and its sub-scales. Cronbach's alpha and relative efficiency were also examined.

RESULTS

FLIC and most of its sub-scales could indicate a clear and statistically significant difference of quality of life (QOL) according to patients' performance status and treatment status. FLIC strongly correlated with FACT-G. The Physical, Psychological, and Symptoms sub-scales of FLIC converged to and diverged from FACT-G sub-scales as conceptually expected. Cronbach's alpha indicated a satisfactory level of reliability. FLIC appeared to be more efficient than FACT-G, meaning that a smaller sample size will be required for FLIC than for FACT-G to achieve the same research purpose.

CONCLUSIONS

The modified version of FLIC was found to have achieved satisfactory measurement properties. This is a user-friendly alternative to the original FLIC.

Size at birth and neonatal and postneonatal mortality

Birthweight is a crude indicator of size at birth. Some neonatologists and obstetricians have advocated the use of ponderal index and birthlength to characterize size at birth. This paper examines the associations between various size-at-birth indicators and neonatal and postneonatal mortality, with an emphasis on ponderal index and birthlength. Size at birth, gestational age and mortality data for about one million babies born alive in Sweden between 1987 and 1995 were collected from the Swedish Medical Birth Registry. A multinomial logit regression was used to estimate conditional odds ratios. Birthlength and ponderal index were independently associated with neonatal and postneonatal mortality. In the latter period, ponderal index was only weakly associated with mortality. The associations were not sensitive to exclusion of cases of congenital anomalies and adjustment for gestational age.

CONCLUSION

Birthlength is strongly associated with both neonatal and postneonatal mortality; ponderal index is strongly associated with neonatal, but weakly with postneonatal mortality. The findings are consistent with previous hypotheses about a transient effect of ponderal index and a persistent effect of birthlength.

The influence of the Chinese zodiac on fertility in Hong Kong SAR

The annual total of births in Hong Kong SAR fell substantially in the past 20 years; hence the total fertility rate (TFR) followed the downward trend and dropped to a low of 0.9 below replacement level in 2000. Despite the long-term downward trend, short-run increases in the annual total of births and the TFR were exhibited. Such temporary fertility increases are identified in the Dragon Years of 1988 and 2000. The phenomenon of fertility changes associated with zodiacal animal years is examined in this paper with a view to gaining some insight into whether Chinese cultural preferences and folklore beliefs might have influenced prospective parents' reproductive behaviour. The paper explains the underlying philosophy of the Chinese astrological tradition and discusses how zodiacal preferences affect fertility between 1976 and 2000. The paper also explores why zodiacal influences on Chinese fertility before 1976 did not exist. It is unquestionable that the Dragon Year preference exerts an influence on fertility of modern Chinese populations through zodiacal birth-timing motivations. Birth rate rise in the Dragon Year is due to changes in timing of births that will have little effect on cumulative fertility.

Association between psychological symptoms in adults and growth in early life: longitudinal follow up study

OBJECTIVES

To test the hypothesis that birth weight for gestational age and weight gain in early childhood have a long term association with psychological distress in adults.

DESIGN

Longitudinal study of 1958 birth cohort followed to age 42 years.

SETTING

Population based birth cohort study.

PARTICIPANTS

9731 cohort members with valid perinatal, postnatal, and adult data.

MAIN OUTCOME MEASURES

Malaise inventory scores measured at ages 23, 33, and 42 years. Generalised estimating equations approach used to analyse repeated measures.

RESULTS

Psychological distress score was inversely related to birthweight z score and weight gain from birth to the age of 7 years. A unit increase in birthweight z score or childhood weight gain was associated with a mean reduction in psychological distress score of 0.10 (95% confidence interval 0.05 to 0.15) and 0.06 (0.02 to 0.10), respectively. Birth weight and weight gain were also inversely related to the odds of having a high level of psychological distress, with odds ratios being 0.90 (0.85 to 0.95) and 0.93 (0.89 to 0.98), respectively.

CONCLUSIONS

Psychological health in adults is related to fetal growth and growth in early childhood.

Benn Index at birth is associated with postnatal linear growth

While previous research has suggested that body thinness is related to subsequent linear growth in children, it is unclear whether thinness at birth is related to linear growth in newborns and catch-up growth in small-forgestational age newborns. Drawing on data from a longitudinal growth study of 3,650 full-term Swedish babies, this study examines linear growth from birth to 6 months of age in three groups of newborns with short (< -2 SDS), appropriate (-2 to 2 SDS) and long (> 2 SDS) body length for gestational age. Among infants short at birth, the Benn Index (kg/m2.69) at birth was not related to the odds of short stature (< -2 SDS) at age 6 months (odds ratio = 1.03; p > 0.10). Nonetheless, the Benn Index was positively related to growth velocity in the first 6 months of life in the short (p = 0.060), appropriate (p < 0.05), and tall (p < 0.05) for gestational age newborns. Use of the Ponderal Index (kg/m3) would give similar results. The findings suggest that nutritional status at birth is related to linear growth velocity in newborns.

Agreement or prediction: asking and answering the right question

INTRODUCTION

Measuring agreement and measuring predictive ability are similar but distinct problems. Failure to appreciate the conceptual and practical differences may lead clinical researchers to give the right answer to the wrong question.

METHODS

We illustrate the relation and difference between measuring agreement and predictive ability in a non-technical way. We provide a real example investigating the feasibility of using preoperative breast cancer tumour size measurements to estimate postoperative histological size. The intraclass correlation and R-squared are calculated to ascertain the level of agreement and predictive ability respectively.

RESULTS

Analysis of agreement and analysis of predictive ability serve different purposes. The optimal solution found in terms of agreement may be different from that found for prediction.

CONCLUSIONS

A careful clarification of the goal of an investigation is important. Using an inappropriate analysis can lead to misleading results, or to results that do not really answer the research question of interest.

Adjustment for selection bias in cohort studies: an application of a probit model with selectivity to life course epidemiology

Sample attrition is potentially a source of bias in cohort studies. The outcome may not be observed in a considerable proportion of the subjects. This article proposes the application of a probit model with sample selection to handle the problem. Two equations are simultaneously estimated and their error terms allowed to correlate: one regressing an observed outcome on a set of baseline variables, another regressing the probability of the outcome being observed upon a set of (perhaps the same) baseline variables. The method was applied to a study of a birth cohort, half of whose members were interviewed again at age 26. Baseline variables were observed for all the subjects included. The focus was on the association between birth weight and mental health in adults. The probit model with sample selection revealed a stronger and more significant (P = 0.037) relation between birth weight and mental health than an ordinary probit regression model (P = 0.170). Interpretation and practical considerations are discussed.

Association between size at birth, paediatric diarrhoeal incidence and postnatal growth

This study tests the hypothesis that size at birth is associated with diarrhoeal incidence from birth to 24 mo of age, and the hypothesis that diarrhoeal incidence from birth to 24 mo is associated with body size at age 24 mo. This is a longitudinal study of 1476 infants born in Lahore. Pakistan, in 1984-1987. Diarrhoeal incidence was enumerated monthly. A generalized estimating equations approach with Poisson regression showed that birthlength standard deviation score (SDS) and ponderal index at birth (rate ratio = 1.01 and 1.00; each p > 0.05) were not significantly associated with diarrhoeal incidence. Multiple linear regression showed that diarrhoeal incidence was significantly associated with weight SDS and body mass index at 24 mo (regression coefficient or beta = -0.58 and -1.02: each p < 0.05). but not with height SDS (beta = -0.10: p > 0.05). The associations were mainly due to a transient effect of diarrhoea in the period 18-24 mo.

CONCLUSION

Prevention of low birthweight is unlikely to have an impact on diarrhoeal incidence in infants. Control of diarrhoeal incidence may not improve the growth of infants in developing countries.

The need for collaboration between clinicians and statisticians: some experience and examples

INTRODUCTION

Very often we see poor communication and collaboration between clinicians and statisticians. Both sides may fail to realise the importance of a truly collaborative effort. In this paper we give examples to illustrate some problems clinicians and statisticians may encounter when they do not have the full support of each other. The aim is to convince both parties the importance of a truly collaborative effort.

METHODS

Real examples in various medical research areas are drawn from the authors' practical experience for illustration. The examples cover various research aspects such as the use of computer software, regression analysis and interpretation of findings.

RESULTS

Superficial collaboration between clinicians and statisticians may lead to serious problems and sub-optimal research practice that may not be obvious in the first sight. Some of the barriers to effective communication and collaboration are discussed.

CONCLUSIONS

On the one hand, robust statistical practice is vital in many medical research projects. On the other hand, medical thinking is important in the formulation and application of statistical strategies. Statistical inputs should be integrated into medical research projects throughout the whole research process. Sporadic contacts between clinicians and statisticians are not enough. Both parties must learn to communicate more effectively and to be willing to collaborate with each other.

Parametric modelling of neonatal mortality in relation to size at birth

We use a richly parameterized model to analyse the effects of shortness and thinness at birth on neonatal mortality in Swedish live-born singletons. The model captures the hazard of neonatal mortality according to the function alpha x exp(-gamma x t) + delta, where t represents age. Covariates are allowed to simultaneously influence the initial excess hazard, the rate of decay, and the long-term hazard. Among term newborns, birth length for gestational age had a stronger effect on the long-term hazard and a weaker effect on the initial excess hazard than the Ponderal index. The initial excess hazard associated with a low Ponderal index tended to decay quickly. Among preterm newborns, a higher birth length for gestational age was associated with lower initial and long-term hazards, and with a faster rate of decay of the initial excess hazard. In contrast, the Ponderal index was not associated with the long-term hazard. We discuss the interpretability of the model and its potential use in neonatology and medical demography. We also compare the model to a Cox model with time-dependent covariates.

Seasonality of growth in Shanghai infants (n=4128) born in 11 consecutive years

OBJECTIVE

To describe the seasonal growth patterns in Shanghai infants, to explore seasonal time lag between weight gain and length gain, and to investigate the long-term effect of birth season on early postnatal growth.

DESIGN

Community-based longitudinal study.

SETTING

Shanghai, People's Republic of China.

METHOD

Children were followed up monthly from 1 to 6 months, 3 monthly from 6 to 12 months, and 6 monthly from 12 to 24 months.

SUBJECTS

A total of 6018 children born between 1 January 1980 and 31 December 1990.

MAIN OUTCOME MEASURES

Weight gain, length gain and change in body mass index (BMI) over the seasons of the year.

RESULTS

The infants tended to grow faster in height in spring and summer, and faster in weight and BMI in autumn and winter. The seasonal effect on weight gain and length gain is largely independent. The mean length value at 1 month of age was about 2.0 cm higher in infants born in May to July than in those born in November to February. At 24 months of age this difference was reduced to about 0.7 cm.

CONCLUSIONS

There is a clear and consistent seasonality in growth in Shanghai infants. The seasonality seems to act independently on weight and length. Birth month has some association with attained size, but this is reduced during the first 2 y of life.

Social patterns of birth weight in Hong Kong, 1984-1997

Fetal growth is an indicator of social inequalities in health that may have a long-term impact persisting into later life. Little is known about the social patterns of birth weight in Hong Kong. This is a study of live-born singletons from 1984 to 1997 in a Hong Kong birth registry. Ordinary least-squares regression and logistic regression are used to analyse birth weight and low birth weight (< 2500 g), respectively. A gradient of birth weight and prevalence of low birth weight is demonstrated according to mothers' educational attainment. In relation to babies of the most educated mothers, babies of the least educated mothers had a mean deficit of 46g in birth weight and an odds ratio of 1.56 of low birth weight (each P<0.05). This social gradient was hidden unless parity was adjusted for. Unexpectedly, migrants from mainland China delivered heavier rather than lighter babies (each P<0.05). Type of living quarters and parental relation were also related to birth weight and low birth weight (each P<0.05). Continuous monitoring of the social patterns of birth weight is recommended.

Fetal growth, early postnatal growth and motor development in Pakistani infants

BACKGROUND

Studies have often compared the postnatal motor development of 'small' versus 'normal' newborns. Not much is known about the associations between a broad spectrum of size at birth and motor development. The effect of early postnatal growth on motor development is little researched. Growth failure in terms of shortness and thinness should be differentiated, but not many studies have the data for this analysis.

METHODS

This is a longitudinal study of infants born in Lahore, Pakistan, between 1984 and 1987. Age at commencement of independent walking and age at 'building a 3-cube tower' were taken as indicators of gross and fine motor development, respectively. Size at birth was captured by length and thinness as continuous variables; postnatal growth from birth to 6 months of age was measured by changes in length and thinness. Adjustment for covariates and handling of censored cases were performed by generalized log gamma regression.

RESULTS

Thinness at birth and postnatal stunting and wasting had a linear, inverse association with gross motor development (each P < 0.05). Birth length had a non-linear, inverse association with this outcome (P < 0.05). Birth length, thinness at birth and postnatal wasting had a linear, inverse association with fine motor development (each P < 0.05).

CONCLUSION

Both fetal and early postnatal growth over a broad spectrum may affect infants' motor development. It is not just the babies who were very small at birth that suffered. Birth length appeared to be more influential than other anthropometric indicators.

Mortality of twins and singletons by gestational age: a varying-coefficient approach

This study used data from the Swedish Medical Birth Registry between 1982 and 1995 to address the question of whether there is higher mortality in twins in relation to singletons of the same gestational age and to examine the optimal gestational age range for twins. A "varying-coefficient approach" was adopted to estimate the gestational age-specific relative and absolute risks of mortality in twins and singletons, adjusting for size at birth and risk factors of short gestational duration. The models showed that twins born between 29 and 37 weeks of gestation had lower mortality than did singletons of the same gestational age. Twins born at older gestational age had higher mortality than did their singleton counterparts, because longer gestational duration was more advantageous to singletons than to twins. Without adjustment for size at birth, there was an upturn of mortality in twins born after 38 weeks. It is postulated that twins have better health than singletons initially, but they could not enjoy the benefit of a longer gestational duration as much as singletons could. The optimal gestational age for twins appeared to be 37-39 weeks according to neonatal and infant mortality.

Secular change in growth over one decade (1980-1990) in Shanghai infants

The aims of this study were to describe secular changes in body size in Shanghai infants, to compare the growth pattern between Shanghai children and Swedish children, and to explore the association of growth rate with parental body size, feeding practice and child health status. The study series consisted of 6,018 longitudinally followed full-term children, born between 1st January 1980 and 31st December 1990 in Fenglin Community, Shanghai. The data clearly show a positive secular trend in growth in Shanghai over the decade of observation; at 12 months, the mean increase in weight and length were 0.32 kg and 0.64 cm, and at 24 months they were 0.54 kg and 1.29 cm. The general growth pattern observed in the children in comparison with the Swedish reference was of fast growth in the first few months of life, and faltering between 9 and 24 months of age. Age at introduction of solid food, weaning age and parental body size were related to growth velocity in the first two years. There was little cumulative effect of diarrhoea on growth in the first two years of life.

Fetal growth and early postnatal growth are related to blood pressure in adults

It is commonly agreed that birth weight is associated with blood pressure in adults. However, not much is known about birth length, ponderal index, and early postnatal growth, whose effects on adult blood pressure, if any, can affect the interpretation of the birth weight-blood pressure association. This study examined the association between fetal growth, early postnatal growth, and blood pressure in Chinese adults. One hundred twenty-two subjects born in Hong Kong in 1967 were followed from birth to age 30 years. Multiple linear regression was used to analyze the association between size at birth, postnatal changes in body size, and systolic and diastolic blood pressure at age 30 years. Having adjusted for potential confounders and each other explanatory variable, it is found that birth length standard deviation score (regression coefficient or beta=-3.2), ponderal index at birth (beta=-1.8), and postnatal changes in ponderal index from age 6 months to 18 months (beta=-2.2) were inversely associated with systolic blood pressure (each P<0.05). Postnatal changes in length standard deviation score were not significantly associated with systolic blood pressure. Birth length standard deviation score was inversely associated with diastolic blood pressure at age 30 years (beta=-2.6; P<0.05). Other anthropometric variables were not associated with diastolic blood pressure. The results support the hypotheses that both fetal growth and early postnatal growth may have a long-term impact on blood pressure in adults. It also highlights the importance of differentiating length and weight for length.

Marital status and mortality in British women: a longitudinal study

BACKGROUND

Most previous studies on marital status and mortality did not adjust for the effect of 'marital selection'. Little research has been done about the relation between marital status and mortality in British women, with the exception of research on bereavement.

METHODS

Subjects consisted of women aged > or = 35 in a longitudinal study of a nationally representative sample. Marital status and covariates were enumerated at a baseline interview in 1984/85 and a follow-up interview in 1991/92. Death data up to May 1997 were obtained from the National Health Service Central Register. Cox regression was used to estimate hazard ratios (HR) for the single, divorced and widowed states in relation to the married state.

RESULTS

Having adjusted for age and martial selection factors, being single (HR = 1.45) was significantly associated with higher all-cause mortality. Being divorced and being widowed showed no excess mortality risk (each HR = 1.09).

CONCLUSIONS

Being single was associated with higher mortality. A causal interpretation is plausible. Being divorced and being widowed were not associated with higher mortality.

The impact of water supplies and sanitation on growth in Chinese children

In many developing countries, improvement in water supplies has not been supplemented by improvement in sanitation facilities. Moreover, health education is rarely included in environmental hygiene programmes. Community health workers need to know if water supplies and sanitation have independent or complementary effects on health. This study analysed the weight data of 1,045 Chinese children aged 60 months or below. Regression models with interaction terms were tested against a model with main effects only. There was no evidence of interaction between water supplies and sanitation measures. The results show that water supplies and toilet facilities had independent associations with growth. Improved water source (P = 0.01) and flush-toilet (P = 0.06) were found positively associated with the children's weight. Presence of excreta in the home had a negative, but not statistically significant, association with weight.

Accidents, assaults, and marital status

Marriage may reduce the risk of accidents and assaults by promoting social control of health behavior. This study examines the impact of marital status on non-fatal accidents and assaults in young British women. Data is drawn from a large cohort study of the people born in 1958. Rate ratios of overall and specific incidence of non-fatal accidents and assaults are determined by negative binomial regression, with adjustment for socio-economic and behavioral confounders. The null hypothesis of no association between marital status and incidence of non-fatal accidents and assaults is rejected. It is suggested that, independent of parental status, more exposure to marriage and less exposure to marital dissolution may reduce accidents and assaults.

Health and adverse selection into marriage: evidence from a study of the 1958 British birth cohort

Despite much research on the relationship between marital status and health, the confounding effects of marital selection are not well understood. Even less is known about 'adverse selection', the phenomenon that people with poor health or health related attributes have a higher chance of marriage. Using data from the National Child Development Study, a longitudinal study of the 1958 British birth cohort, this paper examines the effects of factors that can select single people into early or later marriages. The selection factors are from three domains, namely, health status, socioeconomic status, and risk-taking behaviour. It is found that, from age 16-23 y, adverse selection is prevalent. People from a lower socio-economic background and smokers are more likely to be married. This has the potential to suppress any association between marriage and health. Meanwhile, men with medical problems are less likely to marry. At ages from 23-33 y, adverse selection reduces and those who have better life chances are more likely to get married. This has the potential of creating a spurious relation between marriage and health. These findings shed light on the understanding of the confounding effects of marital selection according to different life stages.