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J W Davis

Publications and source records attributed to J W Davis.

At least 91 records · Page 5Linked to original sources
PubMed1996

A multicenter study of the influence of fat and lean mass on bone mineral content: evidence for differences in their relative influence at major fracture sites. Early Postmenopausal Intervention Cohort (EPIC) Study Group.

We examined the relative influence of fat and lean mass on bone mineral content (BMC) among 1600 early postmenopausal women aged 45-59 y from four geographical locations (Nottingham, United Kingdom; Portland, OR; Honolulu; and Copenhagen). Bone sites investigated included the major fracture sites: hip, spine, and radius. Body weight had strong associations at all skeletal sites examined [BMC differences of 4-6% per interquartile range (IQR) of weight]. Associations with the fat and lean components of weight were more variable. The BMC differences per IQR of lean mass were 5-7% at the hip sites, 3% at the spine, and 2% at the radial sites. The greater differences for lean mass at the hip may reflect the high physical mobility and muscular activity of this site. The BMC differences per IQR of fat mass were 4-6% at the hip sites, 4% at the spine, and 5% at the ultradistal radius. These results suggest that low fat mass or low lean mass, particularly at the extremes, may adversely affect the major fracture sites. The bone sites with the greatest differences for fat mass were the most highly trabecular sites. With only a few exceptions, the associations of BMC with fat mass and lean mass were similar in direction and comparable in magnitude across the four geographic locations. We conclude that both fat and lean mass have independent influences on bone mass, but that their relative influence may vary by bone site depending on the trabecular content, physical mobility, and muscularity of the site.

Adipose Tissue↗
PubMed1996

Anthropometric, lifestyle and menstrual factors influencing size-adjusted bone mineral content in a multiethnic population of premenopausal women.

We report associations of anthropometric, lifestyle and menstrual characteristics with peak bone mass in a multiethnic population of premenopausal women, ages 25-34 y. Four bone sites were examined: the spine, calcaneus, and distal and proximal radius. Body mass index (BMI) was positively associated with bone mass at the spine and calcaneus, the two most trabecular sites. The calcaneus, in addition, was positively associated with an index of calf muscle mass. The distal radius was associated with an arm muscle index, grip strength and the intensity of menstrual flow (light, moderate or heavy). Menstrual flow was also associated with spine bone mass in models not adjusted for BMI; light flow was an indicator of low distal radius or spine bone mass. We hypothesize that light flow may indicate a lack of regular ovulation. The cortical proximal radius was positively associated with milk consumption and height. The magnitude of associations varied by exposure and bone site. Among the strongest associations were BMI at the spine and calcaneus (4 and 7% differences in bone mass per standard deviation), and menstrual flow at the distal radius (a 7% difference between light and heavy menstrual flow). Ethnicity was not statistically significant in multivariable models at any of the four bone sites. However, the prevalence of exposures associated with bone mass varied substantially among the ethnic groups. Ethnic differences in bone mass may have derived indirectly through differences in exposure histories. Other influences of skeletal development may also occur indirectly. Sports activity during adolescence, for instance, was not an independent predictor of bone mass, but sports activity was associated with both strength and muscle mass. Our results suggest that many factors influence peak bone mass, and that the factors vary in importance by skeletal region, possibly related to bone composition and the local intensity of exposure.

Adult↗
PubMed1996

Admission base deficit predicts transfusion requirements and risk of complications.

BACKGROUND: Trauma center resource management could be facilitated by a readily available indicator of resource consumption. This marker should identify patients more likely to require transfusion and intensive care services and to develop complications. Base deficit (BD) has been shown to be a valuable indicator of shock, abdominal injury, fluid requirements, efficacy of resuscitation, and to be predictive of mortality after trauma. This study was performed to determine whether BD could be used to identify which patients were likely to require blood transfusion in the first 24 hours of hospitalization, and to develop shock-related complications and increased intensive care unit (ICU) and hospital stays. METHODS: A retrospective review of 2,954 patients admitted to the Valley Medical Center Level I trauma service from July 1990 through August 1995 was done using the trauma registry and blood bank data bases. Medical record review was done to supplement missing data. RESULTS: Transfusion requirements increased as the BD category became more severe (p < 0.001). Transfusions were required within 24 hours of admission in 72% of patients with a BD < or = -6 versus 18% of patients with a BD > -6 (p < 0.001, chi 2). Both ICU and hospital length of stay increased with worsening BD (p < 0.015 and p < 0.05, respectively). The frequency of adult respiratory distress syndrome (ARDS) (p < 0.01), renal failure (p = 0.015), coagulopathy (p < 0.001), and multiorgan system failure (MOF) (p = 0.002) all increased with increasingly severe BD. Discriminate analysis using Injury Severity Score (ISS) and BD category demonstrated predictive accuracy of 81%, 77%, and 77% for coagulopathy, ARDS, and MOF, respectively. Mortality also increased with worsening BD. When stratified by BD category, there was no difference between observed and predicted survival. CONCLUSIONS: Admission BD identifies patients likely to require early transfusion and increased ICU and hospital stays, and be at increased risk for shock-related complications. Patients with BD < or = -6 should undergo type and cross-match rather than type and screen. The use of ISS and BD category probability curves may identify candidates for early invasive monitoring.

Acid-Base Imbalance↗
PubMed1996

Reduction of benzyl viologen distinguishes genera of the class Mollicutes.

We tested the ability of 62 growing strains belonging to the class Mollicutes to reduce the redox indicator and free-radical generator 1,1'-dibenzyl-4,4'-bipyridinium dichloride (benzyl viologen [BV]) to a blue-violet-purple color. BV was reduced by 12 Acholeplasma species but not by Acholeplasma multiforme PN525T (T = type strain). BV was also reduced by five of nine Mesoplasma species and by four of six Entomoplasma species. BV was not reduced by 19 Mycoplasma species, six Spiroplasma species, five unnamed Spiroplasma strains belonging to different serogroups, three Ureaplasma species, and one unnamed Ureaplasma strain. The BV-reducing ability was localized in the membrane of Acholeplasma laidlawii B-PG9 and was dependent on NADH. Reduction of BV could be expressed in mixed cultures, and this activity may be useful for recognizing the contaminating presence of an Acholeplasma species. The reductive BV response may have phylogenetic value. We believe that the test described in this paper readily distinguishes all Acholeplasma species and some Mesoplasma and Entomoplasma species from all Mycoplasma, Spiroplasma, and Ureaplasma species tested.

Benzyl Viologen↗
PubMed1996

Epidemiologic observations on Parkinson's disease: incidence and mortality in a prospective study of middle-aged men.

We determined age-specific and age-adjusted incidence rates and mortality rates of idiopathic Parkinson's disease (PD) in a cohort of men followed for 29 years. Since enrollment in 1965, the Honolulu Heart Study has followed 8,006 American men of Japanese or Okinawan ancestry. Rescreening of the entire cohort, completed in 1994, included attempts to detect all prevalent and incident cases of PD, parkinsonism, and related conditions. PD incidence rates and age-incidence patterns were similar to rates previously published for Caucasian men in Europe and the United States, and were higher than incidence rates published for Asian men living in Asian nations. Prevalence patterns appeared to correspond more closely to patterns observed in developed nations than in Asian nations. PD was associated with markedly increased mortality that appeared to result from effects of both absolute age and disease duration. There was no firm evidence for differences in birth cohort risks of PD. These data may have implications for maturational and environmental theories of PD etiology.

Aged↗
PubMed1995

High-risk behavior and the public burden for funding the costs of acute injury.

OBJECTIVE: To determine if high-risk behavior is associated with increased injury severity and cost and if public agencies bear a disproportionate burden of that cost. DESIGN: Case comparison study utilizing patient data collected over a 10-year period. SETTING: Five level 1 and 2 trauma centers in an urban-suburban community with a population of 2.4 million. PARTICIPANTS: Trauma registry data from 37,304 consecutive hospitalized adult patients with trauma. Financial data were reported and analyzed on 28,842 of these. MAIN OUTCOME MEASURES: Incidence of alcohol intoxication, other drug use, use of vehicular protective devices, and firearm violence injuries in patients with private vs public health care sponsorship. Length of hospital stay, injury severity, and hospital unit charges were assessed for high-risk behavior. RESULTS: High-risk behavior was more prevalent among trauma patients relying on public funding to cover the costs of their injuries (P < .001). Total hospital unit charges were 28% and 35% higher for motorists not wearing seat belts and motorcyclists not wearing helmets, respectively. Injury severity and length of stay were also higher (P < .001). CONCLUSIONS: High-risk behavior is associated with increased injury severity and cost. Trauma victims exhibiting high-risk behavior more often depend on public agencies to cover the cost of acute injury. Failure to establish and enforce laws and policies designed to reduce or prevent injury may generate enormous trauma care costs, borne to a large extent by public agencies. Further restriction of certain types of high-risk behavior and the institution of "users' fees," taxes, or penalties may be necessary to reduce the disproportionate public agency cost generated by this activity.

Acute Disease↗
PubMed1995

A longitudinal study of estrogen and calcium supplement use among Japanese women living in Hawaii.

BACKGROUND: Estrogen and calcium supplements represent accepted treatments for the prevention of osteoporosis in the United States. The effectiveness of these treatments, however, will depend upon the extent that they are utilized, which may vary over time. METHODS: We report a longitudinal study of estrogen and calcium use among a cohort of Japanese-American women living in Hawaii. Their mean age at the baseline examination in 1981 was 63.9 (age range 45 to 81). Between 1981 and 1992 the same women were repeatedly surveyed regarding their estrogen and calcium supplement use. RESULTS: During the decade of follow-up the prevalence of estrogen use doubled, with 25 to 30% of the women reporting estrogen use in the later years. The prevalence of calcium supplement use (500 mg/day or more) quadrupled over the same interval, with 20% of the women reporting calcium supplement use in the later years. The increases in estrogen and calcium supplement use derived from complex patterns of use. For estrogen, less than half of the users in 1981 were still using 5 years later; the number of women stopping estrogen, however, were more than replaced by new estrogen users. For calcium supplements, fewer than half of the women initiating use continued for as long as 5 years. Women beginning estrogen were younger, had more often used estrogen in the past, had a lower body mass index, had dietary calcium intakes of 400 mg/day or greater, and were more likely to have regularly used alcohol. Women initiating calcium supplements exhibited several of the same characteristics as women initiating estrogen use (younger age, past estrogen use, and regular alcohol use). CONCLUSIONS: The changes in use over the past decade may reduce the risk of osteoporotic fractures among our cohort. Benefits from the changes, however, could be limited by the inconsistent use by many of the cohort women. Also of concern are the weak associations observed between estrogen and calcium supplement use and bone mass measurements, which are strong indicators of fracture risk. It appears that treatment in our cohort has failed to reach many of the women with the greatest fracture risks.

Age Factors↗
PubMed1995

Users of low-dose glucocorticoids have increased bone loss rates: a longitudinal study.

Although high doses of glucocorticoids are believed to cause bone loss, the effects of low glucocorticoid doses are still controversial. Our study examined the effects of low-dose glucocorticoids on the rate of bone loss at three appendicular bone sites. The study population was a cohort of elderly Japanese-Americans, 1094 women and 1378 men. The women were all postmenopausal. At the baseline examination the mean age of the women was 64 years (range 45-81), and the mean age of the men was 68 years (range 61-82). Glucocorticoid users (19 women and 21 men) had used oral systemic or inhaled glucocorticoids on a regular schedule for more than 1 month (mean use was 2.1 years for the women and 1.9 years for the men). The most common dose was equivalent to 5 mg/day of prednisone; fewer than 15% of users had taken doses equivalent to 10 mg/day or more. Changes in bone mass at the calcaneus, distal radius, and proximal radius were documented using bone densitometry at 1 to 2-year intervals over an 8-year period. The initial bone mass of the glucocorticoid users and controls was similar at the baseline examination. The subsequent loss rates among females during glucocorticoid use, however, were approximately double that of the controls. Among males, bone loss rates during glucocorticoid use were 2-3 times that of controls for the calcaneus and radius sites. The differences between glucocorticoid users and controls persisted after adjusting for confounding variables such as age and use of thiazides and estrogens.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Relation of height and weight to the regional variations in bone mass among Japanese-American men and women.

We examined the magnitude of regional variations in bone mass among elderly, Japanese-American men and women. All subjects had bone measurements at the calcaneus, and at the distal and proximal radius sites. A subset of the women had, in addition, spine bone mass measurements. To provide a common measurement scale, the bone measurements were converted to age- and sex-specific Z-scores. The Z-scores between pairs of bone sites were then subtracted to yield the differences in bone mass between bone sites (expressed in Z-score units). For most individuals the differences were less than 1.0 Z-score; however, 12%-20% of the differences were at least 1 Z-score apart. The most similar sites were the distal and proximal radius: different regions within the same bone. Among the other bone pairs, the calcaneus and spine were the most similar to one another. The magnitudes of the differences in bone mass were associated with height and weight. Heavier subjects, for instance, had greater calcaneus than radius bone mass measurements, and greater spine than radius measurements. The spine and calcaneus are more weight-bearing than the radius sites. Associations were observed up to 0.25 Z-score per 10 kg difference in weight. Height was associated with bone mass differences in an opposite direction to weight. Taller subjects had greater bone mass at the radius sites than expected from their calcaneus or spine bone measurements (0.1 to 0.2 Z-score difference per 5 cm difference in height). Bone width partly explained the associations with height; that is, adjusting the radius widths reduced the associations with height. Overall, our results indicate that small to moderate differences between bone sites were common among our study population, and that the magnitudes of the differences were associated with height and weight.

Adult↗
PubMed1995

A randomized, double-masked, placebo-controlled trial of chlorthalidone and bone loss in elderly women.

Employing a double-masked, prospective design, bone loss at three skeletal sites has been monitored among 113 postmenopausal women participating in a placebo-controlled trial of the thiazide-like diuretic chlorthalidone for treatment of systolic hypertension. The mean duration of chlorthalidone use was 2.6 years, at doses of 12.5-25 mg/day. Compared with placebo use, chlorthalidone use was associated with significant reductions in annual bone loss rates. Non-use of chlorthalidone was associated with bone loss at the calcaneus (-0.56% per year) and the proximal radius (-0.91% per year); borderline bone gain was observed at the distal radius (+0.39%). In contrast, chlorthalidone use was associated with bone gain at the calcaneus (+0.44% per year) and the distal radius (+1.51% per year); proximal radius bone loss was significantly reduced to -0.32% per year. The average increment for three appendicular sites was +0.9% per year. These data support a causal relationship between chlorthalidone use and reduced bone loss.

Aged↗
PubMed1995

Analysis of Gulf of Mexico bottlenose dolphins for organochlorine pesticides and PCBs.

Organochlorine concentrations were determined in blubber samples from 33 Tursiops truncatus stranded on the Texas and Florida coastlines. All tissues had measurable concentrations of 4,4'-DDE (0.18-70.7 microg/g lipid weight) and SigmaPCB (4.1-149 microg/g lipid weight). Pesticide and PCB concentrations were similar to those reported in Tursiops truncatus from the Atlantic coast of the United States and the southeast coast of Africa. Organochlorine concentrations were highest in mature males, and differences in the SigmaPCB/SigmaDDT ratios between mature and immature males suggests a recent decrease in DDT uptake, related to the commercial DDT ban in the US in 1971, as well as dietary differences between younger and older animals. Analysis of a female and her calf indicate that females reduce their own organochlorine body burden through transplacental transfer. However, no reduction of some higher molecular weight PCBs was found. Transplacental transfer rates of 5.1% for SigmaDDT and 3.7% for SigmaPCB were determined based on a stranded female and her full term, unborn calf. Predictions of uptake and depuration rates of organochlorines based on gender in Tursiops truncatus agree with clearance rates from previous studies.

Journal Article↗
PubMed1995

Vertebral dimension measurements improve prediction of vertebral fracture incidence.

We investigated the independent contributions of vertebral size and shape, bone density, and existing fractures for predicting the risk of new vertebral fractures among postmenopausal Japanese-American women in Hawaii. Baseline measurements of bone density at the distal and proximal radius and the calcaneus were obtained in 1981, and at the lumbar spine in 1984. Incident fractures were documented on serial radiographs during an average of 8.0 years of follow up of 840 women. A positive difference of 1 standard deviation in vertebral depth increased the risk of new vertebral fractures by approximately 1.3-fold (95% confidence interval = 1.03, 1.66) after controlling for bone density and prevalent fractures. A combination of large vertebral depth (above the 66th percentile) and low bone density (below the 33rd percentile) increased fracture risk approximately six times compared to women with high bone density (above the 66th percentile) and small vertebral depth (below the 33rd percentile). We conclude that combining information about vertebral depth, bone density, and prevalent fracture appears to be better for predicting new fractures than any single variable alone.

Absorptiometry, Photon↗
PubMed1995

Estrogen and calcium supplement use among Japanese-American women: effects upon bone loss when used singly and in combination.

We examined the effects of estrogen and calcium supplementation upon bone loss among a cohort of Japanese-American women. The women averaged 64 years of age (age range 45-81) and 14 years postmenopause at their initial examination in 1981. They returned at 1-3-year intervals for subsequent examinations, most recently in 1992-1994. At each examination, bone mass was measured at the calcaneus and distal and proximal radius. The women had low average dietary calcium intakes (median intake 384 mg/day). Women taking calcium supplements reported a median supplement intake of 355 mg/day; over 75% of the women taking estrogen took the equivalent of 0.6 mg/day or more of conjugated estrogens. Women taking estrogen had uniformly slower bone loss at all three sites. Compared to women not taking estrogen, whose bone loss averaged about 1% per year, women taking estrogen had 0.75-0.85% per year decreased bone loss at the three bone sites. By contrast, women who stopped estrogen had greater than average loss rates (0.35-0.65% per year greater). Calcium supplementation also reduced bone loss, but to a lesser extent than estrogen: bone loss decreased 0.25% per year at the radius sites, but was not slowed at the calcaneus. The calcaneus is more trabecular than the radius sites, which may explain the lack of response. We also examined combined estrogen and calcium supplement use.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Vertebral fracture prevalence in women in Hiroshima compared to Caucasians or Japanese in the US.

BACKGROUND: Although vertebral fractures are very common among elderly Caucasian women, no studies have compared the prevalence to that among Asian populations. Any observed differences in prevalence might lead to the identification of important environmental and/or genetic factors. We therefore compared the prevalence of vertebral fractures among US Caucasians to native Japanese and Japanese immigrants in Hawaii using a standardized approach. METHODS: Spinal radiographs of women aged > 50 years were obtained from native Japanese in Hiroshima, Japanese-Americans in Hawaii, and North American Caucasians in Minnesota between 1982 and 1991. Fractures were defined as vertebral heights > 3 standard deviations (SD) below the vertebra-specific mean. RESULTS: Compared to Japanese-Americans, odds ratios (OR) and 95% confidence intervals (CI) for prevalent vertebral fractures were 1.8 (95% CI: 1.3-2.5) for native Japanese women and 1.5 (95% CI: 1.1-2.1) for Minnesota Caucasians. The OR tended to be higher when comparing the prevalence of two or more fractures per person: OR = 3.2 (95% CI: 2.0-5.3) for native Japanese and OR = 1.9 (95% CI: 1.2-3.2) for Minnesota Caucasians. Similar results were observed for native Japanese using a fracture definition of > or = 4 SD below the mean, but the OR for Caucasians was reduced to 1.2 (95% CI: 0.6-2.3). CONCLUSION: The observation that, among these three populations, hip fracture incidence is lowest but spine fracture prevalence is greatest among native Japanese suggests that different risk factors may be responsible.

Age Factors↗
PubMed1995

Portal triad injuries.

OBJECTIVE: Injuries to the portal triad are a rare and complex challenge in trauma surgery. The purpose of this review is to better characterize the incidence, lethality, and successful management schemes used to treat these injuries. DESIGN: A retrospective review of the experience of eight academic level I trauma centers over a combined 62 years. RESULTS: A retrospective review of the experience of eight anatomical structures of the portal hepatis: 118 injuries to the anatomical structures of the portal hepatis: 55 extrahepatic portal vein injuries, 28 extrahepatic arterial injuries, and 35 injuries to the extrahepatic biliary tree. Sixty-nine percent of the injuries were by penetrating mechanism and 31% were by blunt mechanism. All patients had associated injuries with a mean Injury Severity Score of 34 in blunt trauma patients. Overall mortality was 51%, rising to 80% in patients with combination injuries. Sixty-six percent of deaths occurred in the operating room, primarily from exsanguination; 18% of deaths occurred within 48 hours of injury from refractory shock, coagulopathy, or cardiac arrest; 16% occurred late. Ten percent of patients undergoing portal vein ligation survived, compared to 58% managed by primary repair. Survival after hepatic artery ligation was 42%, compared to 14% after primary repair. Survival after biliary-enteric anastomosis as treatment of extrahepatic bile duct injury was 89%, compared to 50% after primary repair and 100% after ligation of lobar bile duct injuries. Missed bile duct injuries had a high (75%) severe complication rate. CONCLUSIONS: Injuries to the anatomical structures of the portal triad are rare and often lethal. Intraoperative exsanguination is the primary cause of death, and hemorrhage control should be the first priority. Bile duct injuries should be identified by intraoperative cholangiography and repaired primarily or by enteric anastomosis; lobar bile ducts can be managed by ligation.

Adolescent↗
PubMed1995

Clearing the cervical spine in obtunded patients: the use of dynamic fluoroscopy.

OBJECTIVE: Obtunded patients (Glasgow Coma Scale score of < 13) with normal cervical roentgenograms remain in collars until they can be clinically evaluated. Cervical collars provide incomplete immobilization and have complications. Our hypothesis was that cervical spines could be evaluated in obtunded patients with normal cervical roentgenograms using dynamic fluoroscopy. DESIGN: This study was a prospective clinical evaluation. METHODS: Obtunded trauma patients with normal cervical roentgenograms underwent fluoroscopic examination of the cervical spine through a full range of motion. RESULTS: Fluoroscopic evaluations were done in 116 patients. There were 113 true negative examinations. Two patients had facet fractures not diagnosed on cervical roentgenograms, and no instability on fluoroscopy. One patient had a positive exam, with 2 mm of subluxation. There were no neurologic complications. Decubiti were present in 44% and were more frequent when the collar was on > 5 days (p = 0.029). CONCLUSIONS: Dynamic fluoroscopy can safely and effectively clear the cervical spine in obtunded patients. Earlier removal of the collar decreases decubiti.

Adult↗