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Biomedical subjects

Christine Johnson

Publications and source records attributed to Christine Johnson.

7 recordsLinked to original sources
PubMed2006

Bone mineral density in postmenarchal adolescent girls in the United States: associated biopsychosocial variables and bone turnover markers.

PURPOSE: During adolescence, bone formation prevails over resorption, resulting in accumulation of 40% of peak bone mass throughout this time period. Although multiple studies have explored bone mass accrual during the early stages of puberty, less is known about factors that may influence bone accrual during later years of adolescence. In the present cross-sectional study we examined relationships among bone mineral density (BMD) and demographic factors, behavioral variables, and bone metabolism markers in postmenarchal adolescent girls. METHODS: The population was comprised of 389 healthy postmenarchal adolescent girls aged 11-18 years, who were recruited into a prospective study of the effect of depot medroxyprogesterone acetate (DMPA) on bone health in adolescents. At the baseline visit, investigators collected demographic, reproductive health, and lifestyle data, and performed a complete physical examination. Body mass index (BMI) was calculated. Before study initiation, BMD at the lumbar spine, total hip, and femoral neck was measured by dual-energy X-ray absorptiometry (DXA), and markers of bone metabolism (serum bone-specific alkaline phosphatase [BAP], serum osteocalcin, and urinary N-telopeptide [uNTX]) were measured. The baseline data from this study were analyzed to evaluate possible correlates of BMD in postmenarchal adolescent girls. Potential associations between BMD values and other parameters were assessed by analysis of variance and Pearson's correlation coefficient. RESULTS: Participants enrolled in the study had a mean (+/- SD) chronological age of 14.9 +/-1.7 years (range 11-18), mean gynecologic age of 39.9 +/-23.0 months (range 1-120) postmenarche, and mean BMI of 23.5 +/-4.6 kg/m(2) (range 16.0-42.2). Racial/ethnic distribution was 46% African American, 35% Caucasian, and 19% other races; 9% had previously been pregnant. Positive correlations were observed between lumbar spine BMD and chronological age (r = .301, p < .0001), gynecologic age (r = .349, p < .0001), and BMI (r = .371, p < .0001). Total hip and femoral neck BMD values were significantly higher (p < .05 and p < .05, respectively) in African American participants compared with non-African American participants. Previous history of pregnancy was significantly associated with a lower BMD at the lumbar spine (p < .0001) and the total hip (p < .01) when compared with the BMD of adolescents who had never been pregnant. Cigarette smoking and alcohol use were not associated with significant differences in BMD. Negative correlations were observed between gynecologic age and the levels of BAP (r = -.564, p < .0001), osteocalcin (r = -.349, p < .0001), and uNTX (r = -.281, p < .0001), and between lumbar spine BMD and BAP (r = -.363, p < .0001), osteocalcin (r = -.129, p < .05), and uNTX (r = -.202, p < .001) levels. CONCLUSIONS: Our data demonstrate that chronological age, gynecologic age, race/ethnicity, BMI, and previous history of pregnancy are markedly associated with BMD in postmenarchal adolescent girls. Bone accretion in the postmenarchal years continues in the face of a slowdown in bone turnover during this time period.

Adolescent↗
PubMed2006

Folate intake, alcohol use, and postmenopausal breast cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial.

BACKGROUND: Several epidemiologic studies suggest that higher folate intakes are associated with lower breast cancer risk, particularly in women with moderate alcohol consumption. OBJECTIVE: We investigated the association between dietary folate, alcohol consumption, and postmenopausal breast cancer in women from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial cohort. DESIGN: Dietary data were collected at study enrollment between 1993 and 2001. Folate content was assigned on the basis of prefortification (ie, pre-1998) databases. Of the 25 400 women participants with a baseline age of 55-74 y and with complete dietary and multivitamin information, 691 developed breast cancer between September 1993 and May 2003. We used Cox proportional hazard models with age as the underlying time metric to generate hazard ratios (HRs) and 95% CIs. RESULTS: The adjusted HRs were 1.19 (95% CI: 1.01, 1.41; P for trend = 0.04) for women reporting supplemental folic acid intake >/=400 mug/d compared with subjects reporting no supplemental intake. Comparison of the highest with the lowest quintile gave adjusted HRs of 1.04 (95% CI: 0.83, 1.31; P for trend = 0.56) and 1.32 (95% CI: 1.04, 1.68; P for trend = 0.03) for food and total folate intake, respectively. Alcohol consumption was positively associated with breast cancer risk (highest compared with lowest quintile: HR = 1.37; 95% CI: 1.08, 1.76; P for trend = 0.02); the risk was greatest in women with lower total folate intake. CONCLUSIONS: Our results do not support the hypothesis that high folate intake reduces breast cancer risk; instead, they suggest that a high intake, generally attributable to supplemental folic acid, may increase the risk in postmenopausal women. However, our results confirm previous studies showing positive associations between moderate alcohol consumption and breast cancer.

Aged↗
PubMed2005

A pilot study of the effect of Direct Instruction programming on the academic performance of students with intractable epilepsy.

Fifty-five students with intractable epilepsy and learning difficulties, aged 6.5 to 14.1 years with a mean IQ of 71.25 (SD=13.56), attended a hospital-based classroom of no more than eight students where they received Direct Instruction programming for 3 to 4.5 days a week, typically for up to 16 weeks. Pretest-posttest academic gains were evaluated in comparison to normative test performance. At pretest the students were achieving below test means in reading and mathematics, particularly in calculation. Direct Instruction was associated with significant improvement in all academic areas except word identification in reading. IQ level was related to certain academic gains, but gains were not associated with seizure variables or the number of days students spent in the program. Despite severe learning difficulties, students with intractable epilepsy can make academic gains when taught by highly structured teaching methods such as Direct Instruction.

Achievement↗
PubMed2005

Incidence and possible causes of prescribing potentially hazardous/contraindicated drug combinations in general practice.

BACKGROUND: Preventing the use of medications where there is the potential for serious drug-drug interactions or drug-disease interactions (contraindications) is essential to ensure patient safety. Previous studies have looked at the incidence of prescribing contraindicated drug combinations, but little is known about the underlying reasons for the co-prescribing events. The objectives of this study were to estimate the incidence of prescribing contraindicated drug combinations in general practice and to explore the clinical context, possible causes and potential systems failures leading to their occurrence. METHODS: A list of contraindicated drug combinations was compiled according to established references. A search of computerised patient medication records was performed, followed by detailed chart review and assessment. The patient records from four general practices in an area of England were searched for a period of 1 year (1 June 1999-31 May 2000) to identify contraindicated drug combinations. All patients registered with the four participating practices during the study period were included (estimated n = 37 940). Medical records of the cases identified by the computer search were reviewed in detail and relevant information was extracted. Each case was then independently assessed by a pharmacist and a physician who judged whether the co-prescribing was justified and whether it was associated with an adverse drug event. Proximal causes and potential systems failures were suggested for each co-prescribing event. MAIN OUTCOME MEASURES AND RESULTS: Fourteen patients with potential drug-drug interactions and 50 patients with potential drug-disease interactions were identified. Overall, these represent an incidence of 1.9 per 1000 patient-years (95% CI 1.5, 2.3) or 4.3 per 1000 patients being concurrently prescribed > or =2 drugs per year (95% CI 3.2, 5.4). 62 cases involving 63 co-prescribing events were reviewed. Two-thirds of these events involved medications that were initiated by hospital doctors. Awareness of the potential drug-drug or drug-disease interactions was documented in one-third of the events at the time of initial co-prescribing. Within the study period, the co-prescribing was judged to be not justified in 44 events (70%). Potential drug-drug interactions possibly resulted in two adverse drug events. The majority of contraindicated co-prescribing related to drug-disease interactions involved the use of propranolol or timolol eye drops for patients receiving bronchodilators and the use of amiodarone for patients receiving levothyroxine sodium. CONCLUSION: The prescribing of contraindicated drug combinations was relatively rare in this study. Multiple possible causes and systems failures were identified and could be used to develop strategies for the prevention of prescribing errors involving contraindicated drug combinations in primary care.

Contraindications↗
PubMed2003

The electronic patient record in primary care--regression or progression? A cross sectional study.

OBJECTIVES: To determine whether paperless medical records contained less information than paper based medical records and whether that information was harder to retrieve. DESIGN: Cross sectional study with review of medical records and interviews with general practitioners. SETTING: 25 general practices in Trent region. PARTICIPANTS: 53 British general practitioners (25 using paperless records and 28 using paper based records) who each provided records of 10 consultations. MAIN OUTCOME MEASURES: Content of a sample of records and doctor recall of consultations for which paperless or paper based records had been made. RESULTS: Compared with paper based records, more paperless records were fully understandable (89.2% v 69.9%, P=0.0001) and fully legible (100% v 64.3%, P < 0.0001). Paperless records were significantly more likely to have at least one diagnosis recorded (48.2% v 33.2%, P=0.05), to record that advice had been given (23.7% vs 10.7%, P=0.017), and, when a referral had been made, were more likely to contain details of the specialty (77.4% v 59.5%, P=0.03). When a prescription had been issued, paperless records were more likely to specify the drug dose (86.6% v 66.2%, P=0.005). Paperless records contained significantly more words, abbreviations, and symbols (P < 0.01 for all). At doctor interview, there was no difference between the groups for the proportion of patients or consultations that could be recalled. Doctors using paperless records were able to recall more advice given to patients (38.6% v 26.8%, P=0.03). CONCLUSION: We found no evidence to support our hypotheses that paperless records would be truncated and contain more local abbreviations; and that the absence of writing would decrease subsequent recall. Conversely we found that the paperless records compared favourably with manual records.

Adult↗
PubMed2002

Tailored interventions for multiple risk behaviors.

The prevention and management of chronic disease necessitates the effective treatment of health risk behaviors. Evaluating methods for maximizing change among individuals with a combination of these behaviors is an area of continued research. The University of Michigan's Health Media Research Laboratory, in collaboration with the Henry Ford Health System (HFHS), is testing a computer-based tailored print material intervention and complementary telecounseling intervention among individuals served by the HFHS. Both interventions are informed by theoretical constructs, particularly those derived from the Transtheoretical Framework and the Health Belief Model. Through a randomized, 2x2 factorial trial, we intend to determine effectiveness of the two interventions in achieving behavior change of three health risk behaviors: cigarette smoking, low vegetable consumption and sedentary behavior. Participants with at least two of these behavioral risk factors will receive four treatments over an 18-week intervention period. Follow-up at 3 and 12 months will assess both short- and long-term behavioral effects of the individual and combined treatments against a group receiving generic print materials. Through this research, we intend to develop a better understanding of how the presence of multiple risk behaviors affects the probability of behavior change and to evaluate the joint action of these behaviors.

Adult↗