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Cosmetic breast surgery experience and a wide range of mental health, psychosocial, and sociodemographic variables were assessed in the population-based Norwegian Mother and Child Cohort Study (N = 78,252). Breast augmentation patients reported elevated mental health problems. Factors in the domains of physical appearance, drug use, relationships, and exposure to abuse were all related to breast augmentation. Adjusting for such factors reduced the relationships between breast augmentation surgery and all mental health problems to non-significance. Results indicate that the increased prevalence of mental health problems among breast augmentation patients has to be understood from multiple perspectives involving several psychosocial domains. [ABSTRACT FROM AUTHOR]

Knowledge of infant diet and feeding practices among children of mothers with eating disorders is essential to promote healthy eating in these children. This study compared the dietary patterns of 6-month-old children of mothers with anorexia nervosa, bulimia nervosa, binge eating disorder, and eating disorder not otherwise specified-purging subtype, to the diet of children of mothers with no eating disorders (reference group). The study was based on 53,879 mothers in the Norwegian Mother and Child Cohort Study (MoBa). Latent class analysis (LCA) was used to identify discrete latent classes of infant diet based on the mothers’ responses to questions about 16 food items. LCA identified five classes, characterized by primarily homemade vegetarian food (4% of infants), homemade traditional food (8%), commercial cereals (35%), commercial jarred baby food (39%), and a mix of all food groups (11%). The association between latent dietary classes and maternal eating disorders were estimated by multinomial logistic regression. Infants of mothers with bulimia nervosa had a lower probability of being in the homemade traditional food class compared to the commercial jarred baby food class, than the referent (O.R. 0.59; 95% CI 0.36–0.99). Infants of mothers with binge eating disorder had a lower probability of being in the homemade vegetarian class compared to the commercial jarred baby food class (O.R. 0.77; 95% CI 0.60–0.99), but only before adjusting for relevant confounders. Anorexia nervosa and eating disorder not otherwise specified-purging subtype were not statistically significantly associated with any of the dietary classes. These results suggest that maternal eating disorders may to some extent influence the child’s diet at 6 months; however, the extent to which these differences influence child health and development remains an area for further inquiry. [ABSTRACT FROM AUTHOR]

ABSTRACT Aims To investigate associations between maternal stress and smoking prior to, during and 6 months after the pregnancy. Design A prospective population-based cohort study. Setting Norway. Participants A total of 71 757 women in the Norwegian Mother and Child Cohort Study (MoBa) participating twice during pregnancy and at 6 months postpartum. Measurements Respondents' estimates of anxiety and depression, relationship discord and negative life events were measured, along with self-reports of smoking behaviour and demographic variables. Smoking was assessed at gestation weeks 17 and 30 and at 6 months postpartum. Findings Of the 27.5% women who smoked at conception, 55.8% quit smoking during pregnancy. At 6 months postpartum, 28.9% of quitters had relapsed to smoking. In total, 12.9% of the sample reported smoking during the pregnancy. Adjusted for well-known risk factors, women reporting high levels of anxiety and depression had a decreased likelihood of quitting smoking during pregnancy [odds ratio (OR) 0.80, 95% confidence interval (CI): 0.73, 0.88) and an increased likelihood of relapsing after delivery (OR 1.26, 95% CI: 1.11, 1.44). Both relationship discord (OR 0.82, 95% CI: 0.75, 0.90) and exposure to negative life events (OR 0.93, 95%: CI 0.90, 0.96) had a negative influence on quitting smoking during pregnancy but had no influence on relapse to smoking postpartum. Conclusions Maternal stress and relationship discord may inhibit smoking cessation during pregnancy and promote resumption of smoking after pregnancy in women who have achieved abstinence. [ABSTRACT FROM AUTHOR]

Objective: To identify factors associated with incidence and course of broadly defined binge eating disorder (BED) in pregnancy. Method: As a part of the Norwegian Mother and Child Cohort Study (MoBa), 45,644 women completed a questionnaire at approximately 18 weeks of gestation. Results: Incidence of BED was significantly associated with lifetime sexual abuse, lifetime physical abuse, lifetime major depression, symptoms of anxiety and depression, low life satisfaction, low self-esteem, low partner relationship satisfaction, smoking, alcohol use, lack of social support, and several weightrelated factors. Continuation was negatively associated with thoughts of being overweight before pregnancy. Remission was positively associated with thoughts of being overweight before pregnancy and negatively associated with overvaluation of weight. Discussion: Onset of BED in pregnancy was associated with psychological, social and weight-related factors, as well as health behaviors and adverse life events. In women with prepregnancy BED, thoughts of being overweight before pregnancy and overvaluation of weight were associated with course of BED during pregnancy. [ABSTRACT FROM AUTHOR]

Background: Variations in early sexual debut among 16 year olds were investigated by social level variables, parental occupation, gender, ethnicity, family structure, family functioning, and individual level variables, future aspirations, academic and social self-perception, and depressed moods. Methods: The variations in sexual debut were investigated by examining proportions of 16 year olds reporting their first intercourse before age 16. The data were collected by self-reporting questionnaires administered to in-school-youth, in Oslo. Multivariate logistic regression analyses were used to test for associations. Gender interactions with all variables were tested. Results: Overall, 25% reported early debut. Independent effect of social class on differences in proportions in early sexual debut were found. Gender interaction with social class, ethnicity and academic self-perception as they associate to proportions having had early sexual debut, were found. For girls the pattern of social class differences was linear and the highest proportions were found among working classes. For boys the pattern was U-shaped and upper managerial and manual working class youth had similar, higher proportions of early debutants. High scores of parental monitoring, future aspirations and academic self-concept and low scores of depressed moods, are protective factors. While high social self-perception is positively associated with early debut for both genders. Conclusion: Early sexual debut varies according to social class, following gender-specific patterns, among 16 year olds in Oslo. The negative association between early debut and academic self-perception are for boys less influenced by other social and individual level factors, than for girls. [ABSTRACT FROM AUTHOR]

Differences in self-reported delinquency among adolescents in Oslo, Norway, were analysed with respect to immigrant status, gender and country of origin. The survey covered 11,500 adolescents between the ages of 14 and 17 years in Oslo, Norway. Delinquent behaviours were analysed and described in terms of prevalence and frequency. The findings suggest that immigrants are under-represented in minor deviance, with no differences in serious delinquency, but over-represented in violent delinquency. Adolescents with one immigrant parent had a higher prevalence of delinquency compared to adolescents with two immigrant parents, in all categories of delinquency except for violence among males. There were substantial differences between the various immigrant groups, with the lowest prevalence of delinquency among Asians. The study has demonstrated clearly the importance of including different categories of delinquency when studying delinquency among children of immigrants, and to carry out separate analyses according to gender and parent's country of origin. [ABSTRACT FROM AUTHOR]

Introduction and Aims: Adolescent drinking has decreased in numerous high‐income countries in the 2000s, and how to explain this downward trend is far from clear. Focussing on the decline in drinking to intoxication among youth in Norway, we examined the following potential explanatory factors: family/home‐based and peer‐oriented leisure‐time activities, perceived parental drinking, drug substitution, school conscientiousness and delinquency. Design and Methods: Data stemmed from cross‐sectional surveys of adolescents aged 13–17 years in the four largest cities in Norway in 2002 (n = 1204) and in 2013/2015 (n = 31 441). We examined the extent to which the decline in intoxication prevalence was attributable to the possible explanatory variables using logistic regression analysis. Results: The proportion reporting any past‐year intoxication episodes dropped markedly from 2002 (41%) to 2013/2015 (22%). Family/home‐oriented leisure‐time activities and school conscientiousness increased, whereas hanging out with friends in the evening and delinquent behaviours decreased. These factors together accounted for 43% of this decline. Decrease in going out with friends was the most important factor. We found no empirical support for assumptions that perceived parental drinking or drug substitution had contributed to the decrease in drinking to intoxication. Discussion and Conclusions: Since the millennium shift, urban adolescents in Norway have become more home‐, family‐ and school‐oriented, and less involved in unsupervised socialising with peers and delinquency. These changes may have contributed to some of the reduction in the prevalence of intoxication in this population group. [ABSTRACT FROM AUTHOR]

Previous studies of the relationship between maternal eating disorders and adverse perinatal outcomes have failed to control for familial transmission of perinatal phenotypes, which may confound the reported association. In a unique design afforded by the Norwegian Mother and Child Cohort Study and Medical Birth Registry of Norway, we linked three generations through birth register records and maternal-reported survey data to investigate whether maternal eating disorders increase risk after parsing out the contribution of familial transmission of perinatal phenotypes. The samples were 70,881 pregnancies in grandmother-mother-child triads for analyses concerning eating disorder exposure during pregnancy and 52,348 for analyses concerning lifetime maternal eating disorder exposure. As hypothesized, eating disorders predicted a higher incidence of perinatal complications even after adjusting for grandmaternal perinatal phenotypes. For example, anorexia nervosa immediately prior to pregnancy was associated with smaller birth length (relative risk = 1.62; 95% CI [1.20, 2.14]), bulimia nervosa with induced labor (relative risk = 1.21; 95% CI [1.07, 1.36]), and binge-eating disorder with several delivery complications, larger birth length (relative risk = 1.25; 95% CI [1.17, 1.34]), and large-for-gestational-age (relative risk = 1.04; 95% CI [1.01, 1.06]). Maternal pregravid body mass index and gestational weight mediated most associations. Our results support that exposure to eating disorders increases the risk for negative health outcomes in pregnant women and their babies. (PsycINFO Database Record [ABSTRACT FROM AUTHOR]

Objective: We hypothesized that women with eating disorders would be more likely to rate their infants' temperament higher on negative emotionality than women without eating disorders. Method: Of 3,013 mothers with eating disorders, 44 reported anorexia nervosa (AN), 436 bulimia nervosa (BN), 2,475 binge eating disorder (BED), and 58 EDNOS purging type (EDNOS-P). The referent group comprised 45,964 mothers with no eating disorder. A partial proportional odds model was used to estimate the relation among maternal eating disorder presentations and infant temperament ratings while adjusting for covariates. Results: Women with AN, BN, EDNOS-P, and BED were 2.3, 1.4, 2.8, and 1.4 times more likely to report extreme fussiness than the referent group of women with no eating disorder, respectively. Discussion: Mothers with eating disorders may rate their infants as more difficult because of information-processing biases or because their infants are emotionally difficult. Maternal perception of infant temperament may be a risk factor for children's emotional development. © 2012 by Wiley Periodicals, Inc. (Int J Eat Disord 2012) [ABSTRACT FROM AUTHOR]

Fear of childbirth (FOC) is an important women''s health issue. The Wijma Delivery Expectancy/Experience Questionnaire (W-DEQ) is currently the most frequently used instrument to measure FOC. The scale is designed to measure different aspects of FOC but is conceptualized as a uni-dimensional instrument. Our aim was to investigate the underlying factor structure of the W-DEQ version A. A total of 1642 women scheduled to give birth at Akershus University Hospital (Norway) during 2009 and 2010 completed the W-DEQ in the third trimester. Validity and reliability were estimated by means of exploratory and confirmatory factor analyses and correlations with other relevant variables. Results confirmed a multidimensional structure of the W-DEQ. Six factors were identified, each measuring different domains: ''Fear'', ''Negative appraisal'', ''Loneliness'', ''Lack of self-efficacy'', ''Lack of positive anticipation'', and ''Concerns for the child''. The final model resulted in a 25-item version of the instrument with adequate psychometric properties. Subfactors correlated differently with several relevant variables. Especially the factor ''Fear'' was highly correlated with both the overall W-DEQ and several important outcomes. Future studies could examine whether this factor may serve as a good proxy for the full W-DEQ version A. [ABSTRACT FROM AUTHOR]

Objective: Many pregnant women use dietary supplements. Little is known about dietary supplement use during pregnancy in women with eating disorders. Method: We examined dietary supplement use in 37,307 pregnant women, from the Norwegian Mother and Child Cohort Study. Results: Dietary supplement use during pregnancy was as follows: 91.2% of women with anorexia nervosa, 92.2% of women with bulimia nervosa, 93.2% of women with eating disorder not otherwise specified-purging subtype (EDNOS-P), 90.6% of women with binge eating disorder, and 93.5% of the women without eating disorders. Between group differences were not statistically significant. After adjusting for covariates, women with EDNOS-P were more likely to take iron containing supplements (p ⩽ .04). Discussion: Overall dietary supplement use in this sample is similar in women with and without eating disorders. [ABSTRACT FROM AUTHOR]

Objective: The fetal programming model hypothesizes that developmental programming in utero and in early life induces adaptations that predetermine the adult phenotype. This study investigated whether prenatal/perinatal complications are associated with lifetime eating disorders in women. Method: Participants included 46,373 adult women enrolled in the Norwegian Mother and Child Cohort Study (den norske Mor & barn‐undersøkelsen [MoBa]). MoBa mothers and their mothers (MoBa grandmothers) were the focus of the current study. MoBa mothers with lifetime eating disorders were compared to a referent group. Results: MoBa mothers who weighed more at birth (birth weight, adjusted odds ratio [OR] = 1.14; 95% confidence interval [CI]: 1.10–1.19) or were born large‐for‐gestational‐age (adjusted OR = 1.39; 95% CI: 1.27–1.52) were more likely to develop binge‐eating disorder in later life. MoBa mothers who weighed less at birth were more likely to develop anorexia nervosa (birth weight, adjusted OR = 0.88; 95% CI: 0.81–0.95). Bulimia nervosa and purging disorder (PD) were not significantly predicted by the prenatal and perinatal factors examined. Discussion: Results of this study, which include the first known investigation of prenatal and perinatal factors in binge‐eating disorder and PD, suggest that fetal programming may be relevant to the development of anorexia nervosa and binge‐eating disorder. Future genetically informative research is needed to help disentangle whether these associations are a function of genetic influences or a true environmental fetal programming effect. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective The aim of this paper was to internally validate previously reported relations (Knoph Berg et al., Aust N Z J Psychiatry, 42, 396-404, 2008) between psychosocial factors and bulimia nervosa (BN) outcomes during pregnancy. Method This study is based on the Norwegian Mother and Child Cohort Study (MoBa) conducted by the Norwegian Institute of Public Health. Participants were women enrolled during pregnancy ( N = 69,030). Internal validity was evaluated by way of bootstrapped parameter estimates using the overall sample and a split sample calibration approach. Results Bootstrap bias estimates were below the problematic threshold, and extend earlier findings (Knoph Berg et al., Aust N Z J Psychiatry, 42, 396-404, 2008) by providing support for the validity of the models at the population level of all pregnant women in Norway. Bootstrap risk ratios indicated that prevalence, incidence, and remission of BN during pregnancy were significantly associated with psychosocial factors. The split sample procedure showed that the models developed on the training sample did not predict risks in the validation sample. Discussion This study characterizes associations between psychosocial exposures and BN outcomes among pregnant women in Norway. Women with lifetime and current self-reported psychosocial adversities were at a much higher risk for BN during pregnancy. Psychosocial factors were associated with BN remission during pregnancy, inviting the prospect of enhancing therapeutic interventions. We consider the findings in the context of reproducibility in science. © 2014 Wiley Periodicals, Inc. (Int J Eat Disord 2015; 48:654-662) [ABSTRACT FROM AUTHOR]

ABSTRACT Objective To describe weight-for-length (WFL) trajectories in the children (birth-12 months) of mothers with and without eating disorders. Method This study is based on the Norwegian Mother and Child Cohort Study (MoBa) conducted by the Norwegian Institute of Public Health. We categorized women ( N = 57,185) based on diagnosis prior to and during pregnancy: anorexia nervosa, bulimia nervosa, eating disorder not otherwise specified-purging subtype, binge eating disorder, or no eating disorder. The primary analysis included a shape invariant model fitted with nonlinear mixed effects to compare growth rates across eating disorder subtypes. Results The children of mothers reporting any eating disorder had a lower WFL growth rate from birth to 12 months than the children of mothers without eating disorders, even after adjusting for relative birth weight and some confounders known to affect growth. Discussion In this cohort, child WFL was related to maternal eating disorder status before and/or during pregnancy. These differences in growth trajectories warrant further study of long-term health outcomes and, if replicated, tailoring counseling to mothers with eating disorders during pregnancy. © 2014 Wiley Periodicals, Inc. (Int J Eat Disord 2015; 48:406-414) [ABSTRACT FROM AUTHOR]

This study explored the developmental trajectories of postpartum weight from 0.5 to 3 years after childbirth, and aimed to determine the associations between postpartum weight trajectories and prepregnancy body mass index and adequacy of gestational weight gain (GWG). Data from the Norwegian Mother and Child Cohort study were used, following 49,528 mothers 0.5, 1.5, and 3 years after childbirth. Analyses were performed using latent growth mixture modeling. Three groups of developmental trajectories of postpartum weight were found, with most women (85.9 %) having a low level of weight retention initially and slight gain over 3 years, whereas 5.6 % of women started at a high postpartum weight retention (on average 7.56 kg) at 0.5 years but followed by a marked weight loss over time (2.63 kg per year on average), and the third trajectory represented women (8.5 %) who had high weight retention high initially (on average 4.67 kg at 0.5 years) and increasing weight over time (1.43 kg per year on average). Prepregnancy overweight and obesity and excessive GWG significantly predicted a high postpartum weight trend. Women had substantial variability in postpartum weight development-both initially after birth and in their weight trajectories over time. Early preventive interventions may be designed to assist women with prepregnancy overweight and obesity and excessive GWG, which helps to reduce the increasing trend for postpartum weight. [ABSTRACT FROM AUTHOR]

Background Although pregnancy can be associated with adaptive changes in weight and eating behaviour for women with eating disorders, less is known about whether these changes are maintained in the postpartum period. We used a longitudinal design to examine gestational and postpartum weight trajectories in mothers with and without eating disorders in the Norwegian Mother and Child Cohort Study (MoBa) conducted by the Norwegian Institute of Public Health. Methods Fifty-six women reported anorexia nervosa (AN), 636 bulimia nervosa, 3327 binge eating disorder and 69 eating disorder not otherwise specified, purging type. The referent group included 61 233 mothers with no eating disorder. We used a mixed effects model to predict weight change over time by eating disorder subtype. Results Mothers with AN, bulimia nervosa, binge eating disorder and eating disorder not otherwise specified had greater increases in body mass index (BMI) during pregnancy and greater decreases in BMI over the first 6 months postpartum. Women with AN shifted from the underweight BMI range before pregnancy to the normal weight range at 36 months postpartum Conclusions Patterns of maternal weight gain and retention during the perinatal period vary across eating disorder subtype and warrant clinical attention. Copyright © 2014 John Wiley & Sons, Ltd and Eating Disorders Association. [ABSTRACT FROM AUTHOR]

Objective: To investigate course and predictors of eating disorders in the postpartum period. Method: A total of 77,807 women, participating in the Norwegian Mother and Child Cohort Study (MoBa), completed questionnaires during pregnancy including items covering DSM-IV criteria for prepregnancy anorexia nervosa (AN), bulimia nervosa (BN), eating disorder not otherwise specified (EDNOS-P), and binge eating disorder (BED). Additional questionnaires were completed at 18 and 36 months postpartum. Results: Proportions of women remitting at 18 months and 36 months postpartum were 50% and 59% for AN, 39% and 30% for BN, 46% and 57% for EDNOS-P, and 45% and 42% for BED, respectively. However, disordered eating persisted in a substantial proportion of women meeting criteria for either full or subthreshold eating disorders. BN during pregnancy increased the risk for continuation of BN. BMI and psychological distress were significantly associated with course of BED. Discussion: This is the first large-scale population-based study on course of eating disorders in the postpartum period. The results indicated that disordered eating persists in a substantial proportion of women with prepregnancy eating disorders. Health care professionals working with women in this phase of life need to pay specific attention to eating disorder symptoms and behaviors. © 2013 by Wiley Periodicals, Inc. (Int J Eat Disord 2013) [ABSTRACT FROM AUTHOR]

Objective: To examine the amount of weight women with eating disorders [anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED)] gained during pregnancy and to evaluate the adequacy of total weight gain. Method: Data from the Norwegian Mother and Child Cohort Study were used in a cross-sectional manner, n 5 35,148. Descriptive statistics and Generalized Estimating Equations to calculate the relative risk estimates were employed. Results: Mean gestational weight gain for the entire sample was 2.5 kg at 17.0– 20.1 weeks gestation, 9.3 kg at 27.4–29.7 weeks gestation and 15.0 kg at delivery. Women with BN and BED gained significantly more weight on average than those with no eating disorders at each time point. Women with AN had a lower risk (AOR 5 0.65 (0.24, 1.72) of gaining inadequately while women with BN and BED were more likely to gain excessively, AOR 5 1.09 (1.01, 1.18) and 1.11 (1.08, 1.14), respectively. Discussion: The pattern of weight gain identified for each eating disorder subtype may help explain the birth outcomes of women with eating disorders. [ABSTRACT FROM AUTHOR]

There is a lack of research on the role that new media play in the life of young children under the age of 13 years. Hence, the aim of the present study was to investigate the relationship between distinct media user types and social displacement among children under the age of 13. A sample of 1,117 Norwegian school children from the age of 7 to 12 years responded to a questionnaire about their computer game-playing habits and their use of computers, the Internet, mobile phones and television. The results indicate four specific user types reflecting children's various uses of new media: a) Advanced Users, b) Offline Gamers, c) Instrumental Users, and d) Low Users. Some indications of displacement were found between TV, reading and drawing and between new media usage and participation in organized sports activities. At the same time, clear indications support the "more is more" hypothesis, which predicts that active media users will be active children. [ABSTRACT FROM AUTHOR]

This article discusses a study which compared the frequency with which unplanned pregnancies occur in Norwegian women with anorexia nervosa relative to those without eating disorders. The study population consists of 62,060 women. In the sample, 62 reported anorexia nervosa. Researchers used data from a questionnaire completed by all participating mothers. The key findings and conclusion of the study are discussed.

Objective We explored the impact of eating disorders on birth outcomes in the Norwegian Mother and Child Cohort Study. Method Of 35,929 pregnant women, 35 reported broad anorexia nervosa (AN), 304 bulimia nervosa (BN), 1,812 binge eating disorder (BED), and 36 EDNOS-purging type (EDNOS-P) in the six months before or during pregnancy. The referent comprised 33,742 women with no eating disorder. Results Pre-pregnancy body mass index (BMI) was lower in AN and higher in BED than the referent. AN, BN, and BED mothers reported greater gestational weight gain, and smoking was elevated in all eating disorder groups. BED mothers had higher birth weight babies, lower risk of small for gestational age, and higher risk of large for gestational age and cesarean section than the referent. Pre-pregnancy BMI and gestational weight gain attenuated the effects. Conclusion BED influences birth outcomes either directly or via higher maternal weight and gestational weight gain. The absence of differences in AN and EDNOS-P may reflect small numbers and lesser severity in population samples. Adequate gestational weight gain in AN may mitigate against adverse birth outcomes. Detecting eating disorders in pregnancy could identify modifiable factors (e.g., high gestational weight gain, binge eating, and smoking) that influence birth outcomes. © 2008 by Wiley Periodicals, Inc. Int J Eat Disord 2009 [ABSTRACT FROM AUTHOR]

Objective: The purpose of the present study was to investigate the relationship between psychosocial characteristics and broadly defined bulimia nervosa during early pregnancy, including factors associated with continuation, incidence and remission. Method: A total of 41 157 women completed questionnaires at approximately gestation week 18, including items on eating disorders and psychosocial characteristics as a part of Norwegian Mother and Child Cohort Study conducted by the Norwegian Institute of Public Health. Results: Incident bulimia nervosa during the first trimester was significantly associated with symptoms of anxiety and depression and low self-esteem and life satisfaction, whereas remission was significantly associated with higher self-esteem and life satisfaction. Continuation was not significantly related to any of the psychosocial variables tested. Conclusion: Onset of bulimia nervosa during pregnancy is associated with mood and anxiety symptoms. Remission of bulimic symptoms and new onset of bulimia nervosa are associated with opposite profiles of self-esteem, and life satisfaction measures. [ABSTRACT FROM AUTHOR]

Media use has changed considerably during the past five years and earlier research has produced contradictory results on how media use links to children's psychosocial factors. This study charts the access to and use of several media technologies among 825 Norwegian schoolchildren between 10 and 12 years of age. The questionnaire contained items concerning children's self-concept, parental monitoring and social competence. It found that children engage with different kind of media activities and some of these are significantly related to psychosocial factors, however, these correlations were in general quite small. Entertainment usage was associated with low scholastic competence. Both utility usage and heavy advanced usage of new media were related to self-perceptions of athletic competence. Low social acceptance was linked to Gameboy usage and advanced usage of media. Finally, there was a relationship between experienced parental monitoring and utility usage of media technology. The possible implications for these empirical relations are discussed. [ABSTRACT FROM AUTHOR]