Age at marriage and completed family size.
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Adolescent↗
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Areal structure and rates of childlessness among American wives in 1970.
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Adolescent↗
Differential fertility by intelligence: the role of birth planning.
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Adolescent↗
Macroanalytic study of development and fertility: consideration of transition models.
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Developing Countries↗
Breast-feeding, social variables, and infant mortality: a hazards model analysis of the case of Malaysia.
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Adolescent↗
Applications of image analysis to anatomic pathology: realities and promises.
Image Analysis in Pathology is viewed as an ancillary method meant to provide objective support in the resolution of difficult problems. Its Achilles heel is the process of nuclear segmentation (delimitation of the nuclear membrane) which is extremely difficult in pathology materials. Although interactive segmentation procedures are available no reliable fully automatic method has been described. The only application of image analysis that has truly succeeded in Pathology is DNA ploidy measurement. A very desirable application is the quantitation of immunohistochemical markers, which is technically challenging, has been resolved only in certain cases and is unlikely to have a general solution. Nuclear quantitation has repeatedly proven to be helpful in reaching differential diagnoses, in particular when based on size distributions of nuclear profiles rather than its average, but is hampered by the segmentation problem discussed above. Texture analysis of chromatin is an exciting, mathematically complex application likely to succeed, for which many approaches have been described. Finally a diagnosis (classification) can be obtained based on algorithms applied to multiple descriptors of tumor cells (for instance nuclear sizes, chromatin texture, shape, etc). The best classificatory approaches are neural networks (a form of artificial intelligencee), multivariate analysis, and logistic regression (statistical).
Algorithms↗
Comparative pharmacodynamic-pharmacokinetic correlation of oral sustained-release theophylline formulation in adult asthmatics.
A sustained-release formulation of theophylline with an innovative release mechanism was evaluated in adult asthmatics. The pharmacodynamics and pharmacokinetic behavior of this formulation was compared with a market formulation (Theobid). The formulations, each containing 200 mg of anhydrous theophylline, were evaluated in six male subjects, 40-55 years of age, 151-169 cm in height, 41-60 kg in weight, who were nonsmokers with moderate chronic obstructive pulmonary disease (COPD); the study was a randomized, single-dose, open, complete crossover study with an interval of 1 week. Written consent was obtained from the patients prior to the trial. Plasma samples were obtained at 0, 1, 2, 4, 6, 8, 10, and 12 hr postadministration. Pulmonary functions were simultaneously recorded using an Erich Jaeger spirometer. Plasma theophylline assays were performed using high-performance thin-layer chromatography (HPTLC). Individual bioavailability parameters were obtained using the S-Inv computer program. Pharmacodynamic-pharmacokinetic correlation was studied using the Excel 95 version 7.0 Regression Statistics program. The test formulation (innovator) was found to be comparable with the marketed product with respect to tmax, t1/2 and Kel (p < .05). A significant difference in the means of Cmax and AUC0-12 between the innovator and the market formulation indicated a superior extent of absorption from the innovator formulation. A good pharmacodynamic-pharmacokinetic correlation was observed when plasma theophylline concentration was compared with forced expiratory volume.
Administration, Oral↗
Weight gain in adolescents during pregnancy: rate related to birth-weight outcome.
This study of 459 subjects from prenatal clinics for teenagers at three universities across the United States, addresses questions about gestational weight gain in adolescents raised by the 1990 Institute of Medicine Report. Rate and pattern of gain, independent of pregravid weight, are based on serial measures of mothers with favorable and unfavorable outcomes. Rate of gain (determined by using regression statistics) from weeks 15 to 40 was 0.588, 0.510, and 0.488 kg/wk for mothers of term infants weighing 3000-4000 g, term infants weighing < 3000 g, and preterm infants, respectively. The significantly lower percentage of infants weighing 3000-4000 g vs < 3000 g needing intensive care at birth (6% vs 15%, respectively, P < 0.05) further indicates the superior outcome among mothers with higher rates of gain. Rate of gain of mothers of infants weighing 3000-4000 g (favorable outcome) equaled the highest amount provisionally recommended, suggesting that restricting natural gain of adolescents to recommended rates may result in smaller than optimal infants.
Adolescent↗
Evaluation of formulas for calculating total energy requirements of preadolescent children with cystic fibrosis.
BACKGROUND: To support age-appropriate growth and to prevent and treat malnutrition in children with cystic fibrosis (CF), energy requirements for those children are often set above the requirements for healthy children. Care providers use one of several empirically derived formulas to calculate energy requirements, yet the validity of these formulas has seldom been tested. OBJECTIVE: We evaluated 6 proposed formulas for calculating energy requirements in children with CF against a total energy requirement for children with CF (TER-CF) derived from measured total energy expenditure, fecal fat energy loss, and the theoretic energy required for age-appropriate tissue accretion. DESIGN: Subjects were children aged 6-8 y who had CF and pancreatic insufficiency. Calculated TERs from each formula were evaluated against TER-CF by using summary statistics, regression analysis, and residual plots. RESULTS: Subjects (n = 53) had suboptimal nutrition and growth status and mild-to-moderate lung disease. The formula that most closely (within 2%) approximated TER-CF was the estimated energy requirement (EER) formula at the active level (EERact). Regression analysis of TER-CF onto calculated TER from each formula yielded the best indexes of model fit for the EERact formula; residual plots of the EERact formula were tightly and normally distributed around zero. CONCLUSIONS: The EERact formula should be used to establish TER-CF in children in this age group who have mild-to-moderate CF. Changes in weight, height, and other indicators of nutritional status must be monitored to modify TER-CF as needed to support individual patient care goals.
Anthropometry↗
The anti-microbial activity, beta-lactamase stability, and disk diffusion susceptibility testing of carumonam (RO 17-2301, AMA-1080), a new monobactam.
Carumonam, a new monobactam, was found to have an anti-microbial spectrum similar to aztreonam. Its spectrum includes Enterobacteriaceae, Haemophilus influenzae, pathogenic Neisseria species, Pseudomonas aeruginosa, and some streptococci. Staphylococcus species, enterococci, and many other nonenteric gram-negative bacilli were not inhibited. Enterobacteriaceae resistant to cefoperazone (minimum inhibitory concentrations [MICs] greater than or equal to 32 mg/L) were more likely inhibited by carumonam (52% at less than or equal to 8.0 mg/L) than aztreonam (39%) or ceftazidime (35%). Dilution test methods on agar or in Mueller-Hinton broth produced similar results. Carumonam minimum bactericidal concentrations were usually the same or one dilution above the MIC. Carumonam and aztreonam were very stable to most chromosomal (P99, K1, K14) and plasmid-mediated beta-lactamases (TEM, OXA, PSE). The Klebsiella oxytoca enzymes hydrolyzed aztreonam at rates greater than or equal to fivefold higher than carumonam but at a rate less than 1% that of cephaloridine. The aztreonam MICs for these Klebsiella stains were greater than or equal to 32 mg/L, but the hydrolysis rates do not fully explain the high-grade resistance to aztreonam. In vitro susceptibility tests with 30-micrograms carumonam disks were found to be very predictive. Similar regression statistics were observed for aztreonam and cefotaxime. Recommendations for carumonam susceptibility testing are susceptible greater than or equal to 21 mm (less than or equal to 8.0 mg/L) and resistant less than or equal to 14 mm (greater than or equal to 32 mg/L). Cross-resistance analysis favors the independent testing of carumonam or aztreonam against gram-negative species other than Enterobacteriaceae and P. aeruginosa.
Anti-Bacterial Agents↗
Testing for familial correlation in age-at-onset.
The analysis of family-study data sometimes focuses on whether a dichotomous trait tends to cluster in families. For traits with variable age-at-onset, it may be of interest to investigate whether age-at-onset itself also exhibits familial clustering. A complication in such investigations is that censoring by age-at-ascertainment can induce artifactual familial correlation in the age-at-onset of affected members. A further complication can be that sample inclusion criteria involve the affection status of family members. The purpose here is to present an approach to testing for correlation that is not confounded by censoring by age-at-ascertainment and may be applied with a broad range of inclusion criteria. The approach involves regression statistics in which subjects's covariate terms are chosen to reflect age-at-onset information from the subjects's affected family members. The results of analyses of data from a family-study of panic disorder illustrate the approach.
Journal Article↗
Excess deaths attributable to influenza in England and Wales: age at death and certified cause.
The multiple regression statistical method has already been used to estimate excess deaths attributable to influenza in England and Wales by winter period. Now we report further studies of deaths by age group and certified cause of death. During the ten winters since the influenza A/Hong Kong (H3N2) virus first arrived (1968/69 to 1977/78) there have been about 120,000 excess deaths. Of these about 82% were estimated to be in those aged 65+ years, 17% in the 40-64 year age group and 1% in younger adults. Sixty-seven per cent were certified as due to respiratory disease and 31% due to circulatory system disease. Respiratory deaths increased in all age groups during an epidemic, but of the deaths certified as due to circulatory disease, cerebrovascular deaths were mostly in the 65+ age group and ischaemic heart disease deaths in the 40-64 year age group. In this 40-64 year age group there was evidence that the effects of cold weather and epidemic influenza were multiplicative rather than additive. During the worst influenza winter of 1969/70 respiratory deaths increased by approximately 55% and circulatory system deaths by 4%. Deaths in the elderly increased by 10%, in those aged 40-60 years by 8% and in younger adults by 4%. There was no evidence that excess deaths are followed by a deficit during the following year.
Adolescent↗
Comparisons of the in vitro susceptibility testing results for garenoxacin using six different national methods: report from the garenoxacin international bridging study.
BACKGROUND: Laboratories worldwide carry out MIC/disc diffusion (DD) tests using various national methods, often published by local organizations. Potentially different results may complicate drug development or registration between the US methods and those used in the European Union (EU). This study uses a new des-F(6)quinolone, garenoxacin, to compare in vitro results among the most utilized antimicrobial susceptibility testing methods. METHODS: Investigators in France, Germany, Spain, Sweden and the UK tested two bacterial collections designated, challenge (CC; n = 330) containing quinolone-resistant strains and national (NC; n = 540) that were recent clinical isolates (2000-2001). Results were compared with values derived from the National Committee for Clinical Laboratory Standards (NCCLS) methods, carried out by the US coordinating site. Discords (greater than four-fold) between MIC method results were repeated. Results were analysed for variation from the NCCLS results (+/-1-2 dilutions or greater than 3-6 mm) and by regression statistics. Ciprofloxacin was used as the control quinolone agent. RESULTS: CC and NC testing compliance averaged 98.4% and 86.4% among participating centres, respectively, and correlation (r) of the national method to the NCCLS MIC was: France (0.98), Germany (0.95), Spain (0.98), Sweden (0.96) and UK (0.95). CC produced MIC results that were identical to the NCCLS (Spain) to 0.6 x log(2) greater (Germany), but the percentage of strains +/-2 dilutions versus NCCLS MIC results was 98% (Germany)-100% (Sweden, UK). Similar patterns were observed for the NC (r = 0.93-0.98), and all nations had >99% of results within +/-2 dilutions (+/-6 mm for disc tests) of NCCLS values. MIC results from four national methods were slightly elevated compared to the NCCLS result (average 0.2 x log(2)). Control ciprofloxacin MIC and DD test results showed similar patterns. CONCLUSIONS: Inter-method garenoxacin susceptibility test results indicate that MIC and zone diameter endpoints derived from five EU methods compare favourably to the NCCLS method results, and generally were identical or a fraction of a log(2) dilution step higher. In contrast, zone diameters for garenoxacin and ciprofloxacin were routinely larger for the EU methods. This unique inter-method 'bridging' experiment allows regulatory agencies to better correlate in vitro testing results derived from procedures that use different national methodologies.
Anti-Bacterial Agents↗
A homocysteine metabolism-related dietary pattern and the risk of coronary heart disease in two independent German study populations.
A biomarker profile of high folate and vitamin B-12 and low plasma homocysteine concentrations reduces the risk of coronary heart disease (CHD) and may be linked to diet. The objectives of the present study were to identify a food pattern related to these biomarkers and to examine its association with CHD risk. Dietary patterns related to biomarker plasma concentrations were constructed from data obtained in the Coronary Risk Factors for Atherosclerosis in Women (CORA) Study (200 cases; 255 controls) using the reduced rank regression statistical method. Risks for CHD with relation to the identified pattern were estimated in the CORA study and in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study with 157 cases of incident myocardial infarction among 26,795 participants. In these 2 German study populations, whole-grain bread, fresh fruit, olive oil, mushrooms, cruciferous vegetables, wine, and nuts contributed the most positively and fried potatoes the most negatively to a dietary pattern that was directly associated with both plasma folate and vitamin B-12 concentrations, but inversely with plasma homocysteine. Multivariate-adjusted relative risks for CHD across increasing quintiles of the food pattern score were 1.0, 0.55, 0.52, 0.58, 0.39 (P for trend = 0.05) in the case-control sample and 1.0, 0.95, 0.75, 0.56, 0.72 (P for trend = 0.041) in the prospective study. The combination of a high intake of whole-grain bread, fresh fruit, olive oil, mushrooms, cruciferous vegetables, wine, and nuts with a low intake of fried potatoes was associated with a favorable biomarker profile of homocysteine metabolism and reduced risk of CHD.
Aged↗
Rates of U.S. physicians counseling adolescents about smoking.
BACKGROUND: The health care system provides an important opportunity for addressing tobacco use among youths, but there is little information about how frequently physicians discuss smoking with their adolescent patients. We analyzed data from the National Ambulatory Medical Care Surveys to assess the prevalence and the predictors of physicians' identification of smoking status and counseling about smoking at office visits by adolescents. METHODS: From 1991 through 1996, 5087 physicians recorded data on 16 648 visits by adolescents aged 11-21 years. We determined the proportion of office visits at which physicians identified an adolescent's smoking status and counseled about smoking and then identified predictors of these outcomes with logistic regression. Statistical tests were two-sided. RESULTS: In 1991, physicians identified an adolescent's smoking status at 72.4% of visits but provided smoking counseling at only 1.6% of all adolescent visits and 16.9% of visits by adolescents identified as smokers. These proportions did not increase from 1991 through 1996. Compared with specialists, primary care physicians were more likely to identify smoking status (odds ratio [OR] = 1.70; 95% confidence interval [CI] = 1.53-1.89) and to counsel about smoking (OR = 3.43; 95% CI = 2.18-5.38). Patients with diagnoses of conditions potentially complicated by smoking were more likely to have their smoking status identified and to be counseled about smoking. Younger and nonwhite adolescents were less likely to be counseled about smoking than older and white teens. CONCLUSIONS: We found that physicians frequently identified adolescents' smoking status but rarely counseled them about smoking. Physicians' practices did not improve in the first half of the 1990s, despite a clear consensus about the importance of this activity and the publication of physician guidelines targeting this population. Physicians treating adolescents are missing opportunities to discourage tobacco use among teens.
Adolescent↗
Helicobacter pylori seropositivity as a risk factor for pancreatic cancer.
BACKGROUND: Pancreatic cancer is among the most fatal cancers worldwide and one for which few preventable risk factors have been established. Gastric carriage of Helicobacter pylori, particularly cytotoxin-associated gene-A-positive (CagA+) strains, is known to be a risk factor for peptic ulcer disease and gastric cancer and may have a similar etiologic relationship with pancreatic cancer. METHODS: We investigated the association of H. pylori carriage and exocrine pancreatic cancer in a nested case-control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort of 29 133 male Finnish smokers aged 50-69 years at baseline. Case subjects (n = 121) were matched on date of baseline serum collection, study center, age, trial intervention, and completion of the dietary questionnaire to 226 control subjects who were alive at the time the matching case subject was diagnosed and who remained free of cancer, during up to 10 years of follow-up. Levels of immunoglobulin G antibodies to H. pylori whole-cell and CagA+ antigens from stored baseline serum were measured by enzyme-linked immunosorbent assay. Smoking-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by use of conditional logistic regression. Statistical tests were two-sided. RESULTS: Seroprevalence of H. pylori was 82% and 73% among case and control subjects, respectively. Compared with seronegative subjects, those with H. pylori or CagA+ strains were at statistically significantly elevated risk of pancreatic cancer (OR = 1.87 [95% CI = 1.05 to 3.34]; OR = 2.01 [95% CI = 1.09 to 3.70], respectively). CONCLUSIONS: Our findings support a possible role for H. pylori carriage in the development of exocrine pancreatic cancer.
Aged↗
Roles of radiation dose, chemotherapy, and hormonal factors in breast cancer following Hodgkin's disease.
BACKGROUND: Female survivors of Hodgkin's disease (HD) have a strongly elevated risk of breast cancer, but factors responsible for the increased risk are not well known. METHODS: We investigated the effects of radiation dose, chemotherapy (CT), and reproductive factors on breast cancer risk in a nested case-control study in The Netherlands in a cohort of 770 female patients who had been diagnosed with HD before age 41. Detailed treatment information and data on reproductive factors were collected for 48 case patients who developed breast cancer 5 or more years after diagnosis of HD and 175 matched control subjects. The radiation dose was estimated to the area of the breast where the case patient's tumor had developed and to a comparable location in matched control subjects. Relative risks (RRs) of breast cancer were calculated by conditional logistic regression. Statistical tests were two-sided. RESULTS: The risk of breast cancer increased statistically significantly with radiation dose (P(trend) =.01); patients who received 38.5 Gy or more had an RR of 4.5 (95% confidence interval [CI] = 1.3 to 16) times that of patients who received less than 4 Gy. Patients who received both CT and radiotherapy (RT) had a statistically significantly lower risk than those treated with RT alone (RR = 0.45, 95% CI = 0.22 to 0.91). Breast cancer risk increased with increasing radiation dose among patients who received RT only (RR = 12.7, 95% CI = 1.8 to 86, for patients receiving > or =38.5 Gy) but not among patients treated with CT and RT. Sixty-nine percent of control subjects treated with RT and more than six cycles of CT, but only 9% of those who received RT alone, reached menopause before age 41. Reaching menopause before age 36 was associated with a strongly reduced risk of breast cancer (RR = 0.06, 95% CI = 0.01 to 0.45). CONCLUSION: Breast cancer risk increases with increasing radiation dose up to at least 40 Gy. The substantial risk reduction associated with CT may reflect its effect on menopausal age, suggesting that ovarian hormones promote tumorigenesis after radiation has produced an initiating event.
Adult↗
Mortality from lymphohematopoietic malignancies among workers in formaldehyde industries.
BACKGROUND: Many U.S. factory workers are exposed to formaldehyde. Although increased risks for leukemia have been found in medical workers and other professionals exposed to formaldehyde, studies in industrial workers, who are thought to have higher exposures, have shown inconsistent associations. We extended follow-up of a cohort of industrial workers to evaluate the association between formaldehyde exposure and lymphohematopoietic cancers. METHODS: The cohort consisted of 25 619 workers (865 708 person-years) employed before January 1, 1966, at one of 10 U.S. industrial plants and followed through December 31, 1994. We analyzed formaldehyde exposure (peak exposure, average exposure intensity, cumulative exposure, and duration of exposure) and mortality from lymphohematopoietic malignancies using standardized mortality ratios and relative risks and 95% confidence intervals (CIs) based on Poisson regression. Statistical tests were two-sided. RESULTS: Among the cohort, there were 178 deaths from lymphohematopoietic malignancies. Relative risks for leukemia (69 deaths), particularly for myeloid leukemia (30 deaths), increased with formaldehyde exposure. Compared with workers exposed to low peak levels of formaldehyde (0.1-1.9 ppm), relative risks for myeloid leukemia were 2.43 (95% CI = 0.81 to 7.25) and 3.46 (95% CI = 1.27 to 9.43) for workers exposed to peak levels of 2.0-3.9 ppm and > or = 4.0 ppm, respectively (P(trend) =.009). Compared with workers exposed to low levels of average exposure intensity of formaldehyde (0.1-0.4 ppm), workers exposed to 0.5-0.9 ppm and > or = 1.0 ppm average intensity had relative risks of 1.15 (95% CI = 0.41 to 3.23) and 2.49 (95% CI = 1.03 to 6.03), respectively (P(trend) =.088). The relative risk for leukemia was not associated with cumulative exposure but was weakly associated with duration of exposure. Relative risks for Hodgkin's disease also increased with formaldehyde exposure. CONCLUSIONS: Exposure to formaldehyde may cause leukemia, particularly myeloid leukemia, in humans. However, results from other investigations are mixed, suggesting caution in drawing definitive conclusions.
Adult↗