Evidence against the operation of selective mortality in explaining the association between cigarette smoking and reduced occurrence of idiopathic Parkinson disease

To investigate the association between idiopathic Parkinson disease (IPD) and reduced frequency of prior cigarette smoking, the authors compared the 29-year follow-up mortality rates and IPD incidence rates of men who were either cigarette smokers or nonsmokers at the time of enrollment in the Honolulu Heart Study (1965-1968). Based on IPD cases detected up to June 30, 1994, the age-adjusted incidence rate in smokers was less than half that in nonsmokers: 34.4 versus 94.2 cases per 100,000 person-years of pre-illness follow-up, respectively. When data were stratified by 5-year age group, lower IPD incidence in smokers was observed at all ages between 50 and 90 years. Age-specific mortality trends for smokers and nonsmokers with and without IPD suggested that increased mortality in IPD patients was mostly associated with IPD itself and not with smoking. The slight excess mortality in smokers without IPD, versus nonsmokers without IPD, appeared insufficient to account for the "missing" incident IPD cases in smokers. These IPD incidence and mortality data are not highly consistent with the "selective mortality" hypothesis, which attributes reduced prior smoking frequency, typically reported by persons with IPD, to accelerated mortality in undiagnosed IPD-affected persons who smoke. The "protective" association of cigarette smoking with IPD occurrence may thus be real, suggesting the need for further study of biologic mechanisms of protection.

Factors affecting the biodegradation of toluene in soil

The biodegradation of toluene in soil microcosms was examined in order to identify the physical, chemical, and biological factors which determine the fate and lifetime of organic chemicals in soils. Toluene degradation rates were proportional to the initial substrate concentration and these rates reached a maximum at a concentration of 200 micrograms/g. No degradation occurred above this concentration presumably due to the toxicity of the hydrocarbon to the soil microorganisms. Small differences were observed in the degradation rates in soils at different moisture content. However, the availability of water in soil appeared to limit toluene degradation only at a very low water content. The lifetime of toluene in soil was also related to the initial level and activity of the soil microorganisms. Toluene was metabolized rapidly in those soils which initially contained high levels of degrading microorganisms. Furthermore, exposure of the soil to toluene resulted in an increase in the number of degrading organisms. The lack of inorganic nutrients such as nitrogen prevented complete degradation of toluene in a clay soil which contained high levels of degrading microorganisms. The biodegradation of organic chemicals in soil is not an intrinsic property of the molecule and cannot be predicted without first delineating the environment in which it is found. The biodegradation of a compound is defined by the biological, physical, and chemical characteristics of the soil environment. The lifetime of a chemical in soil results from a combination of all three of these parameters.

Assessment of the Frank-Starling relationship by two-dimensional echocardiography

The Frank-Starling relationship between left ventricular stroke work and end-diastolic minor-axis cross-sectional area was evaluated as a load-insensitive measure of inotropic state by two-dimensional echocardiography in 10 conscious dogs. Stroke work was calculated as the product of systolic change in cross-sectional area and either (1) beat-to-beat mean arterial pressure or (2) initial systolic blood pressure. Both Frank-Starling relationships were highly linear during preload variation (mean r = 0.96), sensitive to the inotropic state (slope increase with calcium 51% +/- 43% and 62% +/- 53%, respectively), and insensitive to afterload (r < 0.4, slope or x intercept versus afterload). Thus the Frank-Starling relationships derived from two-dimensional echocardiographic images and peripheral arterial pressure may be a useful and practical means of assessing inotropic state with minimally invasive measurements.

The in vivo quantification of myocardial performance in rabbits: a model for evaluation of cardiac gene therapy

Evaluating cardiac gene therapy in the intact animal requires an index of cardiac function capable of detecting regional differences in contractility in a load-independent fashion. Potentially load-insensitive measures of ventricular performance were therefore evaluated in 10 open- and closed-chested, anesthetized rabbits. LV transmural pressure and myocardial segment length were measured using micromanometry and sonomicrometry during steady-state and transient inferior vena caval occlusion, over a range of inotropic and loading conditions. For each intervention, segmental stroke work was calculated as the area within the left ventricular transmural pressure-length loops at a given end-diastolic segment length during inferior vena caval occlusion; regression analysis was applied to obtain the linear Frank-Starling relationship. In both open- and closed-chested states, these relationships were highly linear (r = 0.97 +/- 0.1) and reproducible. The slope of the linear relationship between segmental stroke work and end-diastolic segment length increased significantly with calcium and epinephrine infusions (P < 0.05 v control) but was not significantly altered by decreased afterload or increased afterload (P > 0.4). The x-intercept was not significantly altered by changes in intropy or afterload (P > 0.4). These data validate the linear Frank-Starling relationship and the slope, MW, as a load-insensitive index of contractility in the intact rabbit. This study presents a novel approach to the quantification of regional cardiac function in smaller animals.

Determinants of vertebral fracture prevalence among native Japanese women and women of Japanese descent living in Hawaii

Age-adjusted prevalence of vertebral fracture has been reported to be higher among native Japanese women than among women of Japanese descent living in Hawaii. In this cross-sectional population-based study, we examined a variety of potential risk factors for associations with prevalent vertebral fractures and investigated whether these factors could explain the difference in vertebral fracture prevalence between native Japanese and Japanese-American women. Spine radiographs and data on spine bone mineral density (BMD) and other potential risk factors were collected among 802 Japanese women aged 50-88 years living in Hiroshima and 840 Japanese-American women aged 52-88 years living in Hawaii. In logistic regression analysis, BMD was a major predictor of prevalent vertebral fracture. In linear regression models, weight, age, and menstrual history (age at menopause or years between menarche and menopause) were significantly associated with BMD and thus might contribute to fracture risk indirectly through their effects on BMD. However, age and menstrual history provided additional and complementary information about fracture prevalence after adjusting for BMD. These variables together explained much of the difference in vertebral fracture prevalence between the two study populations. We conclude that the observed difference in age-adjusted prevalence of spine fracture between native Japanese and Japanese-American women was accounted for primarily by the differences in BMD, duration of estrogen exposure, and/or duration of estrogen deficiency. Thus, current BMD is a major but not the sole risk factor for vertebral fractures. Age-related and menopause-related mechanisms may also play an important role in spine fracture independent of BMD.

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.

Contributions of vertebral fractures to stature loss among elderly Japanese-American women in Hawaii

Loss of stature is a typical feature of osteoporosis and associated vertebral fractures. However, there have been few prospective population-based studies to estimate the magnitude of this association. Further, the separate contributions of different types of vertebral fractures to stature loss have not been evaluated using prospective data. In this study we investigated the extent to which stature loss could be explained by the number of different types of vertebral fractures (wedge, endplate, and crush fractures) after adjusting for other covariates. Longitudinal data on stature loss and vertebral fractures were collected among 504 postmenopausal Japanese-American women living in Hawaii with mean age 73.4 (SD 4.9) years. During an average of 7.7 years of follow-up, women with at least one incident vertebral fracture had an average of 2.1 cm of stature loss while the average stature loss among those without incident fractures was only 0.4 cm. The mean rate of stature loss was very slight (< 1 mm/year) for those without incident vertebral fractures even after age 80. Our analyses suggest that both the number of wedge and the number of crush fractures are strong predictors of stature loss. After adjusting for age and total height loss in the anterior dimension over T3-L5, the estimated stature loss resulting from each wedge and crush fracture was 0.86 and 1.08 cm, respectively. Endplate fractures did not show significant contributions to stature loss.

Postdischarge geriatric assessment of hospitalized frail elderly patients

BACKGROUND

The diffusion of comprehensive geriatric assessment services has been rather limited in North America partly because of reimbursement and organizational constraints.

OBJECTIVE

To evaluate the impact of a comprehensive geriatric assessment intervention for frail older patients that is started before hospital discharge and is continued at home.

METHODS

Patients older than 65 years were selected who had either unstable medical problems, recent functional limitations, or potentially reversible geriatric clinical problems. Patients (n = 354) were randomly assigned to either the intervention group or a control group. Information on survival, readmissions, nursing home placement, medication use, and health status was collected at 30 and 60 days after hospital discharge.

RESULTS

No differences were observed between the two treatment groups in survival, hospital readmission, or nursing home placement by 60 days. After adjustment for baseline characteristics, no significant differences were observed between the two groups on measures of physical functioning, social functioning, role limitations, health perceptions, pain, mental health, energy and/or fatigue, health change, or overall well-being.

CONCLUSIONS

Although efficacy has been demonstrated for some forms of comprehensive geriatric assessment, the types of services that are easier to establish (inpatient consultation services and ambulatory assessment) have not been shown to improve outcomes. Our results indicate that outcomes are unaffected by a limited form of comprehensive geriatric assessment begun in the hospital and completed at home. Further efforts are needed to develop and to evaluate realistic approaches to comprehensive geriatric assessment.

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.

Neurogenic pulmonary edema in fatal and nonfatal head injuries

Impaired pulmonary function is a frequent but poorly understood complication of acute head injury (HI). A potential early contributor to the pulmonary dysfunction seen in HI patients is neurogenic pulmonary edema (NPE). We hypothesized that NPE would occur early after HI and that it would have a continuum of clinical severity depending on the severity of the HI and associated intracranial hypertension. A large autopsy data base and inpatient HI data base were used to search for cases of NPE. Patients in the autopsy data base were stratified according to injury type and whether they died at the scene or within 96 hours of injury. There were significant (p < 0.0001, analysis of variance) elevations in lung weights in patients dying at the scene and within 96 hours from HI, compared with those dying from other noncentral nervous system injuries. No other organs studied showed significant weight increases. The incidence of NPE in isolated HI patients dying at the scene was 32%. In patients with isolated HI dying within 96 hours, the incidence of NPE was 50%. We found an inverse correlation (r = 0.62; p < 0.0014) between the initial cerebral perfusion pressure and the PaO2/FIO2 ratio despite a normal-appearing chest x-ray film. We conclude that NPE occurs frequently in HI patients. The process of edema formation begins early in the clinical course and is isolated to the lung.(ABSTRACT TRUNCATED AT 250 WORDS)

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)

Iliofemoral venous injuries: an indication for prophylactic caval filter placement

Prophylactic placement of vena caval filters is recommended in trauma patients at high risk for pulmonary embolism (PE). We present a group of patients with iliofemoral venous trauma, and subsequent complications of deep venous thrombosis (DVT) and PE. Of twelve patients with iliac or common femoral venous injuries, seven underwent primary repair. All received DVT/ PE prophylaxis with mini-dose heparin and/or sequential compression hose. In spite of this, two patients suffered DVT, one patient had DVT and PE and one patient had clinical evidence of PE but did not undergo confirmatory testing. Three patients underwent prophylactic caval filter placement without complication. The DVT/PE complication rate in this small group was at least 43% (3 of 7). Patients with repaired iliofemoral venous injuries represent a high risk subset for DVT/PE and prophylactic caval filter placement is recommended.

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.

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.

Mechanical determinants of myocardial oxygen consumption in conscious dogs

A new practical descriptor of metabolic to mechanical myocardial energy transfer (MET), termed the virtual work model, was evaluated in 32 conscious dogs and in 8 isolated canine hearts. An index of total mechanical energy expenditure (TME) was calculated as the sum of external energy (stroke work) and an internal energy index of heat (left ventricular end-diastolic volume times left ventricular mean ejection pressure). Physiological comparison of TME (x-axis) and myocardial oxygen consumption (MVO2; y-axis) yielded highly linear MET relationships (mean r = 0.93 +/- 0.07), with an average slope of 0.86 +/- 0.39 (SD) and a y-intercept of 9.1 +/- 6.4 mW/ml myocardium. The linear MVO2-TME relationship did not vary under steady-state vs. dynamic vena caval occlusion, increased heart rate, increased afterload, or increased inotropic state with calcium infusion. Compared with five other indexes of myocardial energetics, the virtual work model of MET was the most linear, the most practical in not requiring determination of the end-systolic pressure-volume relationship, and the most accurate predictor of MVO2 under normal and altered hemodynamic conditions.

Trampoline-related injuries

Two hundred and seventeen patients who had sustained an injury during the recreational use of a trampoline were managed in the emergency room of Logan Regional Hospital in Logan, Utah, from January 1991 through December 1992. We retrospectively reviewed the charts and radiographs of these patients to categorize the injuries. Additional details regarding the injuries of seventy-two patients (33 per cent) were obtained by means of a telephone interview with use of a questionnaire. The injuries occurred from February through November, with the peak incidence in July. The patients were eighteen months to forty-five years old (average, ten years old); ninety-four patients (43 per cent) were five to nine years old. Eighty-four patients (39 per cent) sustained a fracture; fifty-four (25 per cent), a sprain or strain; forty-five (21 per cent), a laceration; and thirty-four (16 per cent), a contusion. Fifty-seven injuries (26 per cent) involved the elbow or forearm; forty-six (21 per cent), the head or neck; forty (18 per cent), the ankle or foot; thirty-three (15 per cent), the knee or leg; nineteen (9 per cent), the trunk or back; thirteen (6 per cent), the shoulder or arm; and nine (4 per cent), the wrist or hand. Thirteen patients (6 per cent) had a back injury, but none of them had a permanent neurological deficit. One patient who had an ocular injury was transferred to a tertiary care center. One hundred and fifty-six patients (72 per cent) were evaluated radiographically, fifteen (7 per cent) were admitted to the hospital, and thirteen (6 per cent) had an operation.(ABSTRACT TRUNCATED AT 250 WORDS)

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)

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.

S-(1,2-dichlorovinyl)-L-cysteine-induced nephrotoxicity in the New Zealand white rabbit: characterization of proteinuria and examination of the potential role of oxidative injury

S-(1,2-dichlorovinyl)-L-cysteine (DCVC)-induced nephrotoxicity in vivo was investigated in New Zealand White rabbits. A primary emphasis in these studies was further characterization of DCVC-induced nephrotoxicity using a variety of serum and urinary analytes, including sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Additionally, the role of oxidative injury was assessed to address the dichotomy between reports indicating that such a mechanism is important in vivo and those indicating that such mechanisms do not contribute substantially to the mechanism of effects observed in vitro. Urine was collected prior to and at 8 and 24 hr after iv administration of DCVC. Serum was collected 15 min prior to and 24 hr after DCVC administration. Rabbits were euthanized 24 hr post-DCVC administration, and kidneys were fixed in formalin and further processed for light microscopic examination. DCVC (10 mg/kg, iv) induced a 45-50-fold increase in total urinary protein excretion, a 10-15-fold increase in urinary N-acetyl-beta-D-glucosaminidase concentration, plus a marked glucosuria by 24 hr postadministration. Additionally, DCVC increased serum creatinine levels by about 2-fold, with a trend toward increased blood urea nitrogen. SDS-PAGE analysis of rabbit urine confirmed the clinical finding of marked proteinuria in DCVC-treated animals, which in contrast to previously reported data was due to the presence of both low and high molecular weight proteins. Antioxidants had no significant effect on DCVC-dependent renal injury, nor was there evidence for DCVC-induced lipid peroxidation, as measured by either thiobarbituric acid-reactive substances or a commercial assay for malondialdehyde and hydroxalkenals.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

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.

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.

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.