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Biomedical subjects

L B Dixon

Publications and source records attributed to L B Dixon.

At least 19 recordsLinked to original sources
PubMed2006

Radiographic texture analysis of densitometer-generated calcaneus images differentiates postmenopausal women with and without fractures.

INTRODUCTION: Bone fragility is determined by bone mass, measured as bone mineral density (BMD), and by trabecular structure, which cannot be easily measured using currently available noninvasive methods. In previous studies, radiographic texture analysis (RTA) performed on the radiographic images of the spine, proximal femur, and os calcis differentiated subjects with and without osteoporotic fractures. The present cross-sectional study was undertaken to determine whether such differentiation could also be made using high-resolution os calcis images obtained on a peripheral densitometer. METHODS: In 170 postmenopausal women (42 with and 128 without prevalent vertebral fractures) who had no secondary causes of osteoporosis and were not receiving treatment for osteoporosis, BMD of the lumbar spine, proximal femur, and os calcis was measured using dual energy x-ray absorptiometry. Vertebral fractures were diagnosed on densitometric spine images. RTA, including Fourier-based and fractal analyses, was performed on densitometric images of os calcis. RESULTS: BMD at all three sites and all texture features was significantly different in subjects with and without fractures, with the most significant differences observed for the femoral neck and total hip measurements and for the RTA feature Minkowski fractal (p<0.001). In univariate logistic regression analysis, Minkowski fractal predicted the presence of vertebral fractures as well as femoral neck BMD (p<0.001). In multivariate logistic regression analysis, both femoral neck BMD and Minkowski fractal yielded significant predictive effects (p=0.001), and when age was added to the model, the effect of RTA remained significant (p=0.002), suggesting that RTA reflects an aspect of bone fragility that is not captured by age or BMD. Finally, when RTA was compared in 42 fracture patients and 42 nonfracture patients matched for age and BMD, the RTA features were significantly different between the groups (p=0.003 to p=0.04), although BMD and age were not. CONCLUSION: This study suggests that RTA of densitometer-generated calcaneus images provides an estimate of bone fragility independent of and complementary to BMD measurement and age.

Adult↗
PubMed2006

Obesity among individuals with serious mental illness.

OBJECTIVE: To study the distribution and correlates of body mass index (BMI) among individuals with serious mental illness. METHOD: A total of 169 participants were recruited from randomly selected out-patients receiving community-based psychiatric care and were interviewed with items from the National Health and Nutrition Examination Survey (NHANES) III. Their BMI was compared with that of 2404 matched individuals from the NHANES data set. RESULTS: The distribution of BMI in the psychiatric sample significantly differed from that of the comparison group; 50% of women and 41% of men were obese compared with 27% and 20% in the comparison group. Within the psychiatric sample, higher BMI was associated with current hypertension and diabetes, a wish to weigh less, and reduced health-related functioning. CONCLUSION: Obesity is more prevalent among individuals with serious mental illness than in demographically matched individuals from the US general population. Among persons with mental illness, obesity is associated with co-occurring health problems.

Adolescent↗
PubMed2001

Let the pyramid guide your food choices: capturing the total diet concept.

This paper discusses how the guideline "Eat a variety of foods" became "Let the Pyramid guide your food choices," presents background information on the food guidance system upon which the Food Guide Pyramid is based and reviews methods that have been used to assess aspects of the total diet, i.e., the variety, moderation and proportionality, promoted by this guidance. The methods include measures of dietary variety, patterns based on Pyramid food group intakes and scoring methods comprised of multiple dietary components. Highlights of results from these methods include the following. Although approximately one third of the U.S. population eat at least some food from all Pyramid food groups, only approximately 1-3% eat the recommended number of servings from all food groups on a given day. Fruits are the most commonly omitted food group. Vegetables and meat are the groups most commonly met by adults, and dairy the most commonly met by youth. Intakes of specific types of vegetables (i.e., dark green, deep yellow) and of grains (i.e., whole grains) are well below that recommended; intakes of total fat and added sugars exceed current recommendations. Scoring methods show those diets of the majority of the population require improvement, and that diets improve with increases in education and income. This paper also discusses the limitations and strengths of these approaches, and concludes with suggestions to improve current food guidance and methods to assess the total diet.

Age Factors↗
PubMed2001

Choose a diet that is low in saturated fat and cholesterol and moderate in total fat: subtle changes to a familiar message.

"Choose a diet that is low in saturated fat and cholesterol and moderate in total fat," issued in Nutrition and Your Health: Dietary Guidelines for Americans in the year 2000, has an interesting and lengthy history. The first guideline, for which there was extensive scientific data to show that dietary excess increased chronic disease risk, prompted much scientific discussion and debate when implemented as dietary guidance. Three major changes in the guideline are noted since it was issued in 1980, i.e., numerical goals for dietary fats; the applicability of recommended fat intakes for all individuals > or =2 y old; and rewording to emphasize reducing saturated fat and cholesterol intakes. The shift in emphasis includes the terminology moderate fat, which replaces the phrasing low fat. National data about the food supply, the population's dietary intake, knowledge, attitudes and behaviors, and nutritional status indicators (e.g., serum cholesterol levels) related to dietary fats help to monitor nutrition and health in the population. Experts consider that national data, although not without limitations, are sufficient to conclude that U.S. intakes of fats, as a proportion of energy, have decreased. The lower intakes of saturated fat and cholesterol are consistent with decreases in blood cholesterol levels and lower rates of coronary mortality over the past 30 years. Strategies are needed and some are suggested, to further encourage the population to achieve a dietary pattern that is low in saturated fat and cholesterol and moderate in total fat. Other suggestions are offered to improve national nutrition monitoring and surveillance related to the guideline.

Age Factors↗
PubMed2001

Dietary intakes and serum nutrients differ between adults from food-insufficient and food-sufficient families: Third National Health and Nutrition Examination Survey, 1988-1994.

Approximately 10.2 million persons in the United States sometimes or often do not have enough food to eat, a condition known as food insufficiency. Using cross-sectional data from the Third National Health and Nutrition Examination Survey (NHANES III), we examined whether dietary intakes and serum nutrients differed between adults from food-insufficient families (FIF) and adults from food-sufficient families (FSF). Results from analyses, stratified by age group and adjusted for family income and other important covariates, revealed several significant findings (P < 0.05). Compared with their food-sufficient counterparts, younger adults (aged 20-59 y) from FIF had lower intakes of calcium and were more likely to have calcium and vitamin E intakes below 50% of the recommended amounts on a given day. Younger adults from FIF also reported lower 1-mo frequency of consumption of milk/milk products, fruits/fruit juices and vegetables. In addition, younger adults from FIF had lower serum concentrations of total cholesterol, vitamin A and three carotenoids (alpha-carotene, beta-cryptoxanthin and lutein/zeaxanthin). Older adults (aged > or =60 y) from FIF had lower intakes of energy, vitamin B-6, magnesium, iron and zinc and were more likely to have iron and zinc intakes below 50% of the recommended amount on a given day. Older adults from FIF also had lower serum concentrations of high-density lipoprotein cholesterol, albumin, vitamin A, beta-cryptoxanthin and vitamin E. Both younger and older adults from FIF were more likely to have very low serum albumin (<35 g/L) than were adults from FSF. Our findings show that adults from FIF have diets that may compromise their health.

Adult↗
PubMed2000

Differences in energy, nutrient, and food intakes in a US sample of Mexican-American women and men: findings from the Third National Health and Nutrition Examination Survey, 1988-1994.

As Mexican-American women and men migrate to the United States and/or become more acculturated, their diets may become less healthy, increasing their risk of cardiovascular disease. Data from the Third National Health and Nutrition Examination Survey (1988-1994) were used to compare whether energy, nutrient, and food intakes differed among three groups of Mexican-American women (n = 1,449) and men (n = 1,404) aged 25-64 years: those born in Mexico, those born in the United States whose primary language was Spanish, and those born in the United States whose primary language was English. Percentages of persons who met the national dietary guidelines for fat, fiber, and potassium and the recommended intakes of vitamins and minerals associated with cardiovascular disease were also compared. In general, Mexican Americans born in Mexico consumed significantly less fat and significantly more fiber; vitamins A, C, E, and B6; and folate, calcium, potassium, and magnesium than did those born in the United States, regardless of language spoken. More women and men born in Mexico met the dietary guidelines or recommended nutrient intakes than those born in the United States. The heart-healthy diets of women and men born in Mexico should be encouraged among all Mexican Americans living in the United States, especially given the increasing levels of obesity and diabetes among this rapidly growing group of Americans.

Acculturation↗
PubMed2000

Diet quality of young children who received nutrition education promoting lower dietary fat.

OBJECTIVE: : To evaluate the impact of nutrition education promoting lower dietary fat on the overall diet quality in children using a multidimensional index that measures nutrient and food intakes in relation to US dietary recommendations. DESIGN: : Prospective cohort study with two intervention and two control groups. Children with elevated low density lipoprotein (LDL) cholesterol were randomized to one of two intervention groups or an at-risk control group. The intervention children received either the parent-child autotutorial (PCAT) programme, a 10-week home-based self-instruction nutrition education programme, or nutrition counselling from a registered dietitian. Children with non-elevated plasma cholesterol formed the not-at-risk control group. Dietary and blood data were collected at baseline and at 3 months. SETTING: : Paediatric practices in suburbs north of Philadelphia, PA. SUBJECTS: : Two hundred and twenty-seven 4-10-year-old children with elevated LDL cholesterol between the 80th and 98th percentiles, and 76 age- and gender-matched children with non-elevated plasma cholesterol, were studied. RESULTS: : Children who received PCAT or counselling significantly improved their overall diet quality (-0.6 and -0.4 change in diet quality index (DQI) scores) compared with at-risk control children. Children who received either form of nutrition education were more likely to meet the recommendations for three components of the DQI (total fat, saturated fat, sodium) (OR >1.7), but did not improve their intakes of three components of the DQI (vegetables and fruits, complex carbohydrates, calcium) at 3 months. CONCLUSIONS: : Nutrition education promoting lower dietary fat improved children's overall diet quality. However, several dietary behaviours important for long-term health remained unchanged.

Analysis of Variance↗
PubMed2000

A focus group pilot study of tobacco smoking among psychosocial rehabilitation clients.

OBJECTIVE: The study explored the perceived advantages and disadvantages of tobacco smoking and quitting among clients in psychosocial rehabilitation programs. Deeper understanding of such perceptions may be useful in creating maximally effective cessation and prevention interventions for this population. METHODS: Five focus groups of six to ten persons were formed with a total of 40 clients from two programs. Participants included smokers and nonsmokers-including former smokers and smokers who explicitly were not interested in quitting smoking. The semistructured, researcher-facilitated discussions covered pros and cons of smoking and not smoking, barriers to and facilitators of abstinence, and other issues. Audiotapes of the group discussions were transcribed and analyzed qualitatively. RESULTS: Participants emphasized their reasons for smoking, reasons for quitting or wanting to quit, views on smoking-related health concerns, perceived social costs and benefits of smoking, and strategies for quitting and maintaining abstinence. Many similarities between the focus groups' views and those of the general population were noted, along with some issues that are specific to having a mental illness or attending a psychosocial rehabilitation program, such as coping with psychiatric symptoms and limited access to information, support, and other coping methods. All of these views influenced participants' motivations and perceived readiness to smoke or to abstain, or to struggle between the two alternatives. CONCLUSIONS: Issues and needs that are specific to smokers who use mental health services must be addressed in the development of smoking prevention and cessation interventions in psychosocial rehabilitation and other mental health programs. The importance of messages about smoking that clients receive from program rules, program staff, and other sources is highlighted, as is the possibility that the regulation of affect and stress provided by tobacco use is especially important for people experiencing psychiatric symptoms.

Adaptation, Psychological↗
PubMed1999

The Pathways study: a model for lowering the fat in school meals.

We describe the development and implementation of the Pathways school food service intervention during the feasibility phase of the Pathways study. The purpose of the intervention was to lower the amount of fat in school meals to 30% of energy to promote obesity prevention in third- through fifth-grade students. The Pathways nutrition staff and the food service intervention staff worked together to develop 5 interrelated components to implement the intervention. These components were nutrient guidelines, 8 skill-building behavioral guidelines, hands-on materials, twice yearly trainings, and monthly visits to the kitchens by the Pathways nutrition staff. The components were developed and implemented over 18 mo in a pilot intervention in 4 schools. The results of an initial process evaluation showed that 3 of the 4 schools had implemented 6 of the 8 behavioral guidelines. In an analysis of 5 d of school menus from 3 control schools, the lunch menus averaged from 34% to 40% of energy from fat; when the menus were analyzed by using the food preparation and serving methods in the behavioral guidelines, they averaged 31% of energy from total fat. This unique approach of 5 interrelated food service intervention components was accepted in the schools and is now being implemented in the full-scale phase of the Pathways study in 40 schools for 5 y.

Asian People↗
PubMed1998

Adolescents engaging in unhealthy weight control behaviors: are they at risk for other health-compromising behaviors?

OBJECTIVES: This study sought to determine whether adolescents engaging in weight control behaviors are at increased risk for tobacco, alcohol, and marijuana use; suicide ideation and attempts; and unprotected sexual activity. METHODS: Data were collected on a nationally representative sample of 16,296 adolescents taking part in the 1993 Youth Risk Behavior Survey. RESULTS: Adolescents using extreme weight control behaviors were at increased risk for health-compromising behaviors, while associations with other weight control behaviors were weak and inconsistent. CONCLUSIONS: The findings have relevance to clinical work with youth, provide a better understanding of disordered eating, and open up a number of opportunities for future research.

Adolescent↗
PubMed1997

A randomized trial of assertive community treatment for homeless persons with severe mental illness.

BACKGROUND: This experiment evaluated the effectiveness of an innovative program of assertive community treatment (ACT) for homeless persons with severe and persistent mental illnesses. METHODS: One hundred fifty-two homeless persons with severe and persistent mental illness were randomized to either the experimental ACT program or to usual community services. Baseline assessments included the Structured Clinical Interview for DSM-III-R, Quality-of-Life Interview, Colorado Symptom Index, and the Medical Outcomes Study 36-Item Short Form Health Survey. All assessments (except the Structured Clinical Interview) were repeated at the 2-, 6-, and 12-month follow-up evaluations. RESULTS: Subjects in the ACT program used significantly fewer psychiatric inpatient days, fewer emergency department visits, and more psychiatric outpatient visits than the comparison subjects. The ACT subjects also spent significantly more days in stable community housing, and they experienced significantly greater improvements in symptoms, life satisfaction, and perceived health status. CONCLUSIONS: Relative to usual community care, the ACT program for homeless persons with severe and persistent mental illness shifts the locus of care from crisis-oriented services to ongoing outpatient care and produces better housing, clinical, and life satisfaction outcomes.

Activities of Daily Living↗
PubMed1997

Comorbid bulimia nervosa and schizophrenia.

OBJECTIVE: Despite literature citing the frequency of abnormal eating behavior in persons with schizophrenia, little attention has been paid to the comorbidity of eating disorders and schizophrenia. This case review explores the comorbidity of bulimia nervosa and schizophrenia and its possible clinical implications. METHOD: The authors present four case reports of women with rigorously diagnosed schizophrenia who have eating-disordered behavior. RESULTS: The first case describes a woman whose bulimia nervosa clearly preceded the onset of her schizophrenia. The second and third cases describe women who have many characteristics and risk factors for bulimia nervosa and whose bulimic symptoms significantly interact with psychotic symptoms. The fourth case describes a woman with bulimic behavior which is clearly responsive to psychosis. She does not have a history and behavioral profile of true bulimia nervosa. DISCUSSION: These case reports extend support to a model that schizophrenia and bulimia may coexist in a complex, interactive fashion with important clinical implications.

Adult↗
PubMed1997

Effects of family history of heart disease, apolipoprotein E phenotype, and lipoprotein(a) on the response of children's plasma lipids to change in dietary lipids.

We examined the effects of family history of coronary artery disease (CAD), apolipoprotein E (apo E) phenotype, and lipoprotein(a) [Lp(a)] on the response of plasma lipids to change in dietary lipid intake after 3 mo of nutrition education in 125 children aged 4-10 y. The subjects were healthy children with elevated low-density-lipoprotein (LDL)-cholesterol concentrations who participated in the Children's Health Project, a nutrition-education program designed to lower plasma cholesterol by means of dietary modifications in accordance with recommendations of the National Cholesterol Education Program. Dietary and plasma lipids were measured by three 24-h recalls and assessments of two fasting plasma samples collected before and 3 mo after the start of intervention. Family history of CAD was determined by questionnaires administered to parents at baseline. Apo E phenotyping was done with isoelectric focusing followed by immunostaining; Lp(a) was measured with two-site immunoradiometric assays of frozen aliquots of plasma samples collected at baseline and 3 mo. After adjustment for intervention group, age, sex, and body mass index, analysis of covariance showed that baseline plasma lipid concentrations were the strongest independent predictors of change in plasma lipids after 3 mo. Plasma total and LDL-cholesterol concentrations in children with less family history of CAD were significantly more responsive to change in dietary cholesterol than concentrations in children with a stronger family history of CAD. Neither apo E phenotype nor Lp(a) significantly influenced change in plasma lipids independently or interactively with change in dietary lipids.

Apolipoproteins E↗
PubMed1997

The effect of changes in dietary fat on the food group and nutrient intake of 4- to 10-year-old children.

OBJECTIVE: To determine how young children changed their overall diet when they changed their fat intake after 3 months of participating in a nutrition education demonstration study designed to lower low-density lipoprotein cholesterol and cardiovascular risk. METHODS: Three 24-hour dietary recalls were collected from 303 4- to 10-year-old children at baseline and 3 months later. At both times, mean number of servings from food groups, grams of fat contributed from food groups, and intake of calories and nutrients were calculated and compared among quartiles of children formed according to change in their percent of calories from total fat after 3 months. RESULTS: Children who reduced their percent of calories from total fat most (ie, by an average of 8.5%) after 3 months consumed fewer servings from meats, eggs, dairy, fats/oils, and breads but tended to increase their number of servings from lower-fat foods within those food groups, particularly from dairy foods. These children also increased their mean intake of fruits, vegetables, and desserts, and maintained average intakes of all nutrients (except vitamin D) in excess of two thirds of the respective recommended dietary allowance. CONCLUSIONS: Young children who reduced their percent of calories from total fat in accordance with the current National Cholesterol Education Program recommendations accomplished this by reducing their overall intake of higher-fat foods, replacing higher-fat foods with lower-fat foods within several food groups, particularly within the dairy group (eg, drinking skim milk instead of whole milk) and by consuming more servings of fruits, vegetables, and very-low-fat desserts. These behaviors did not compromise their mean calorie or nutrient intakes, showing that it is possible for young children to lower their fat intake safely to reduce their risk of future heart disease.

Child↗
PubMed1996

Change in nutrient intakes, number of servings, and contributions of total fat from food groups in 4- to 10-year-old children enrolled in a nutrition education study.

OBJECTIVE: To determine change in nutrient intakes, number of servings, and contributions of total fat from food groups in children who lowered their dietary fat intake. DESIGN: A research and demonstration study designed to lower plasma low-density lipoprotein cholesterol level. There were four study groups: two intervention and two control groups. All children had hypercholesterolemia except for those in one control group. There 24-hour dietary recalls were collected on randomly assigned days over a 2-week period at baseline and 3 months after the intervention. SUBJECTS: Three hundred three 4-to 10-year old children from suburbs north of Philadelphia, Pa. INTERVENTIONS: One intervention involved a home-based, parent-child autotutorial program (PCAT group) with audiotaped stories and print materials for the children and their families; the other intervention involved one face-to-face counseling session with a registered dietitian (counseling group). OUTCOME MEASURES: Change in mean nutrient intakes compared with the Recommended Dietary Allowance (RDA); change in number of servings and mean grams of total fat contributed from 10 different food groups. STATISTICAL ANALYSES PERFORMED: Analyses of variance and chi 3 analyses. RESULTS: Children in every study group had mean intakes of all nutrients (except vitamin D) greater than 67% of the RDA 3 months after the baseline measurement. Several food groups (ie, meats, dairy products, fats/oils, and desserts) provided less total fat to the diets of children who reduced their dietary lipid intake after 3 months (i.e., PCAT and counseling groups). These children also reduced the mean number of servings selected from these food groups. Within these same food groups, some children consumed fewer servings of higher fat foods and more servings of lower fat foods. APPLICATIONS/CONCLUSIONS: Children who lowered their dietary fat intake after intervention reported both quantitative and qualitative changes in food choices from several food groups. These choices did not significantly reduce their nutrient intakes.

Aging↗
PubMed1996

Detection of substance use disorders among psychiatric inpatients.

This study examines the utility of the Addiction Severity Index (ASI) for detecting psychoactive substance use disorders (PSUDs) among psychiatric inpatients. Four hundred thirty-five inpatients at two inner-city psychiatric hospitals completed the ASI and the Structured Clinical Interview for DSM-III-R (SCID). Receiver operating characteristic (ROC) analysis assessed the optimal threshold ASI alcohol and drug composite scores to detect DSM-III-R PSUDs. The correlations of both the ASI alcohol and drug composite scores with their corresponding DSM-III-R PSUD categories were significant (p<.0001). However, the ROC analysis revealed that the ASI misses approximately 20% of SCID-positive PSUD cases. Specificity of the ASI, on the other hand, is quite good (95% to 98%), and optimal ASI threshold scores to rule out a PSUD among these patients are identified. The results also support the sensitivity of these patients to the toxic effects of illicit substance use.

Alcoholism↗