Biomedical subjects

D Sparrow

Publications and source records attributed to D Sparrow.

At least 19 recordsLinked to original sources

PubMed2001

Bone lead and blood lead levels in relation to baseline blood pressure and the prospective development of hypertension: the Normative Aging Study.

Between 1991 and 1997, the authors studied 833 participants of the Normative Aging Study in a substudy of bone lead levels (measured by K-shell x-ray fluorescence), blood lead levels, and hypertension. Among these subjects, 337 were classified as normotensive, and 182 and 314 were classified as having borderline and definite hypertension, respectively, at baseline. These bone and blood lead levels were typical of those of community-exposed men. Among the 519 subjects with no history of definite hypertension at baseline, cross-sectional analyses revealed positive associations between systolic blood pressure and bone lead levels. Of the 474 subjects who were free from definite hypertension at baseline and had follow-up data, 74 new cases of definite hypertension were reported. Baseline bone lead levels were positively associated with incidence of hypertension. In proportional hazards models that controlled for age, age squared, body mass index, and family history of hypertension, an increase in patella (trabecular) lead from the midpoint of the lowest quintile to that of the highest quintile was associated with a rate ratio of definite hypertension of 1.71 (95% confidence interval: 1.08, 2.70). No association was found with blood lead level. These results support the hypothesis that cumulative exposure to lead, even at low levels sustained by the general population, may increase the risk of hypertension.

Adult↗

PubMed2001

Receiver operating characteristics curve analysis of cutaneous skin test reactions to predict hay fever and asthma symptoms in the Normative Aging Study.

BACKGROUND: We used receiver operating characteristic (ROC) curves to determine optimal cutoff values and to evaluate the ability of ragweed, mixed grasses, mixed trees, and house-dust antigens to predict symptoms of hay fever and asthma. METHODS: Between 1984 and 1993, 1386 members of the Normative Aging Study cohort had at least one examination that included evaluation of cutaneous hypersensitivity to common aeroallergens by skin prick testing. Standard questionnaires based on the American Thoracic Society DLD-78 questionnaire obtained information on respiratory symptoms, illness, and smoking habits. RESULTS: Ragweed was the best univariate predictor for both hay fever and asthma symptoms: the area under the ROC curve for hay fever was 0.71 (95%) CI 0.67-0.74); for asthma, it was 0.65 (95% CI 0.55-0.75). For hay fever, dichotomizing the average reaction to four antigens at 2 mm gave a sensitivity of 56% and a specificity of 83%; at 3 mm, the sensitivity was 38% and specificity 92%. For asthma, dichotomizing the skin test reaction at 2 mm gave a sensitivity ranging from 30% for reaction to mixed grasses to 56% for the ragweed antigen reaction. CONCLUSIONS: Although in this older population skin test reactivities did not predict current asthma symptoms with high sensitivity, our results support the use of cutoff values of 2 or 3 mm as commonly used in studies of hay fever symptoms.

Adult↗

PubMed2001

A telephone-linked computer system for COPD care.

The current revolution in communications technology provides an opportunity for novel approaches to management of medical illness. As economic imperatives lead to a progressive reduction in the time that health-care providers spend with their patients, computerized, telephone-linked communication systems offer an inexpensive, widely available alternative with which patients and providers can maintain contact. Such systems may be particularly useful for providing ongoing monitoring and education of patients with chronic illnesses such as COPD. In this article, we describe the general application of telephone-linked communication systems in the health-care setting. We then present in detail one such system, which provides telephone-linked care for COPD (TLC-COPD). The operation of the system is described, as are its theoretical underpinnings in social learning theory. A randomized clinical trial currently is being performed to study the effects of the TLC-COPD system. The rationale for expected improvements in disease control and quality of life, and for a reduction in acute health-care utilization, is discussed.

Algorithms↗

PubMed2000

A prospective study of dominance and coronary heart disease in the Normative Aging Study.

The purpose of this study was to examine the prospective relation between dominance, as assessed by a Minnesota Multiphasic Personality Inventory (MMPI-2)-derived dominance scale, and incidence of coronary heart disease (CHD), independent of participants' anger level. The study was performed in the VA Normative Aging Study, an ongoing cohort of older (mean age 61 years) men. A total of 1,225 men who were free of CHD in 1986 completed the MMPI-2. A factor analysis of selected MMPI items provided the basis for the construction of a dominance scale and an anger scale. During an average of 8 years of follow-up, 158 cases of incident CHD occurred, including 29 cases of fatal CHD, 69 cases of nonfatal myocardial infarction (MI), and 60 cases of angina pectoris (AP). Compared with men reporting the lowest levels of dominance (lower tertile), the multivariate-adjusted relative risk among men reporting the highest levels of dominance (upper tertile) was 1.80 (95% confidence interval [CI] 1.21 to 3.24) for combined nonfatal MI and fatal CHD. Additional adjustment for anger scores did not significantly alter this relation. There was no significant relation between dominance and AP. Our data suggest that dominance is an independent risk factor for CHD in older men.

Adult↗

PubMed2000

Subdivision of the cardiac Nkx2.5 expression domain into myogenic and nonmyogenic compartments.

Nkx2.5 is expressed in the cardiogenic mesoderm of avian, mouse, and amphibian embryos. To understand how various cardiac fates within this domain are apportioned, we fate mapped the mesodermal XNkx2.5 domain of neural tube stage Xenopus embryos. The lateral portions of the XNkx2.5 expression domain in the neural tube stage embryo (stage 22) form the dorsal mesocardium and roof of the pericardial cavity while the intervening ventral region closes to form the myocardial tube. XNkx2.5 expression is maintained throughout the period of heart tube morphogenesis and differentiation of myocardial, mesocardial, and pericardial tissues. A series of microsurgical experiments showed that myocardial differentiation in the lateral portion of the field is suppressed during normal development by signals from the prospective myocardium and by tissues located more dorsally in the embryo, in particular the neural tube. These signals combine to block myogenesis downstream of XNkx2.5 and at or above the level of contractile protein gene expression. We propose that the entire XNkx2.5/heart field is transiently specified as cardiomyogenic. Suppression of this program redirects lateral cells to adopt dorsal mesocardial and dorsal pericardial fates and subdivides the field into distinct myogenic and nonmyogenic compartments.

Animals↗

PubMed2000

Optimism and depression as predictors of physical and mental health functioning: the Normative Aging Study.

Dispositional optimism has been linked in previous studies to better health outcomes. We sought to examine the independent associations of dispositional optimism and depressive symptoms with physical and mental functioning in a cohort of healthy middle-aged and older men. The study was conducted among 659 subjects in the Veterans Administration (VA) Normative Aging Study. Dispositional optimism and depressive symptomatology were measured in 1991 and 1990, respectively, by the Life Orientation Test and the Center for Epidemiologic Studies--Depression Scale (CES-D). The dependent variables, functioning and well-being, were measured in 1992 by the Medical Outcomes Study Short-Form Health Survey (SF-36). In multivariate regression models, optimism was associated with higher levels of general health perceptions, vitality, and mental health, and lower levels of bodily pain, but not to physical functioning, social functioning, or role limitations due to physical or emotional problems. Depressive symptomatology was associated with reduced levels of functioning across all SF-36 domains. The findings for optimism and depression were statistically significant after mutual adjustment in multivariate regression models. Optimism and depression are independent predictors of functional status among aging men.

Aged↗

PubMed2000

Maximal and partial expiratory flow rates in a population sample of 10- to 11-yr-old schoolchildren. Effect of volume history and relation to asthma and maternal smoking.

The effect of volume history on forced expiratory flow rates has been reported to differ between patients with asthma and healthy persons, and it has been hypothesized that the peripheral airway inflammation of patients with asthma may underlie this difference. There are no published data, however, on the distribution of such volume history effects or the relation of these effects to airways disease in children. We obtained combined partial and maximal forced expiratory flow-volume curves on 1,834 children, age 10-11 yr, in eight communities in the United States and Canada. The effect of a deep inhalation on forced expiratory flow rates at low lung volumes was quantitated by the ratio of V (30) during a maximal expiratory maneuver (V (30M)) to V (30) during a partial expiratory maneuver (V (30P)). The V (30M)/V (30P) ratio was slightly higher among girls than boys (1.26 versus 1.18, p = 0.0001) indicating that a deep inhalation increased V (30) slightly more among girls than among boys. The V (30M)/V (30P) ratio was related to neither history of asthma nor to maternal smoking. In contrast, most spirometric indices from either the maximal or the partial expiratory flow-volume curve were lower in association with a history of asthma or a report of maternal smoking. The ratio of FEF(25-75)/FVC was particularly consistent as a measurement that discriminated both of these effects in boys and girls. These results suggest that the measurement of volume history effects offers no benefits for epidemiological studies of childhood respiratory disease whereas spirometric indices such as the FEF(25-75)/FVC ratio are quite sensitive to the effects of asthma and environmental tobacco smoke exposure on the airways.

Asthma↗

PubMed2000

Quality of dyspnea in bronchoconstriction differs from external resistive loads.

To test the hypothesis that patients perceive the same quality of dyspnea during mild bronchoconstriction and external resistive loads, we studied subjects with asthma under two conditions: (1) during methacholine bronchoprovocation to mimic the bronchospasm of mild asthma and (2) while breathing on a circuit to which was added a range of external resistors to mimic the mechanical load of mild asthma. During each of these stimuli, respiratory variables, overall dyspnea intensity on a modified Borg scale, and the qualitative descriptors of breathlessness from a 19-item questionnaire were assessed. The "chest tightness" and "constriction" responses were significantly more frequent in the methacholine trials as compared with the external load trials (p < 0.0001). The "chest tightness" or "constriction" response was chosen during 92% of the 26 trials of methacholine bronchoconstriction compared with 3% of the 72 trials of breathing against the external resistors. Changes in functional residual capacity were not significantly different between the two conditions. We conclude that in mild asthma, the sensation of chest tightness is distinct from the sensation of work and effort and is not attributable to the mechanical load imposed on the respiratory system.

Adult↗

PubMed2000

Effect of low level lead exposure on hyperuricemia and gout among middle aged and elderly men: the normative aging study.

OBJECTIVE: To determine whether longterm lead accumulation is associated with hyperuricemia and gouty arthritis among middle aged and elderly men. METHODS: In a retrospective cohort study, 777 male participants were evaluated between August 1991 and October 1996 in the Department of Veterans Affairs Normative Aging Study, a 35 year longitudinal study of aging. We examined the development of gout and an increased uric acid level in relation to lead, adjusting for other known risk factors. Lead levels were measured in blood and by K x-ray fluorescence (K-XRF) technique in tibial (cortical) and patellar (trabecular) bone. RESULTS: Blood lead levels in this mostly Caucasian (97%) population were low (mean 5.9 microg/dl, SD 3.5). Bone lead levels were comparable to those described in other general populations. In a multivariate analysis adjusting for the risk factors, age, body mass index, diastolic blood pressure, alcohol intake, and serum creatinine level, there was a positive association between patellar bone lead and uric acid levels (p = 0.02). Of 777 participants, 52 (6.7%) had developed gouty arthritis. In logistic regression of similar covariates, body mass index (p < 0.0001) and serum creatinine level (p = 0.005) were the strongest determinants of gout; neither bone nor blood lead levels predicted gout in this cohort. CONCLUSION: The longterm accumulation of lead is associated with an increased uric acid level in middle aged and elderly men. However, this study shows no association between lead and gouty arthritis at the levels arising from community exposure.

Age Factors↗

PubMed1999

Relations between individual and neighborhood-based measures of socioeconomic position and bone lead concentrations among community-exposed men: the Normative Aging Study.

To examine the association between lead exposure and both individual and geographic area indicators of socioeconomic position, the authors measured tibia lead concentration, a biomarker of cumulative lead exposure, using K x-ray fluorescence in a cross-sectional survey of 538 white males aged 50-92 years who were healthy when enrolled in the Normative Aging Study (Boston, Massachusetts) in the 1960s. Data on individual risk factors, education, occupation, and income were collected by questionnaire. Using subjects' residential addresses at the time of the tibia lead measurements, the authors obtained geographic area-specific measures of education, social class, and poverty by linking records to 1990 US Census block group data. In multivariate linear regression analysis controlling for age and cumulative smoking, tibia lead concentrations were 10.39 microg/g (95% confidence interval (CI) 7.80-12.97) higher in men who did not graduate from high school than in men with > or =4 years of college. Among the former men (non-high school graduates), living in an undereducated area was associated with a 9.28 microg/g (95% CI 1.59-16.97) increase in tibia lead level compared with living in a non-undereducated area; among the latter men (college graduates), no difference existed by residential area education (beta = 0.72, 95% CI -5.35 to 6.78). The authors conclude that the influence of individual socioeconomic position on cumulative lead exposure is modified by geographic area conditions.

Adult↗

PubMed1999

Socioeconomic status, hostility, and risk factor clustering in the Normative Aging Study: any help from the concept of allostatic load?

OBJECTIVE: To examine the relationships between socioeconomic status (SES), psychosocial vulnerability (hostility), and allostatic load. Allostatic load refers to the cumulative physiological cost of adaptation to stress. METHOD: We examined the relationships between SES (as measured by educational attainment), hostility, and allostatic load in the Normative Aging Study, a longitudinal study of community-dwelling men aged 21 to 80 years and free of known chronic medical conditions at entry in the 1960s. In 1986, the revised Minnesota Multiphasic Personality Inventory was administered by mail, from which a hostility measure was derived by summing the scores from three Cook-Medley subscales: Hostile Affect, Hostile Attribution, Aggressive Responding. An index of allostatic load was constructed from data collected during physical exams conducted between 1987 and 1990 (i.e. measures reflecting "wear and tear" on the cardiovascular, endocrine, and metabolic systems). Cross-sectional relationships between education, hostility, and allostatic load were examined in 818 men. RESULTS: Separate linear regression analyses indicated that lower levels of educational attainment and greater hostility were both associated with higher allostatic load scores (p < .05 and p < .01, respectively). Less education was also associated with higher hostility (p < .001). When allostatic load was regressed simultaneously on education and hostility, the effect of education was attenuated, while hostility (p < .05) maintained an independent effect. CONCLUSIONS: Our findings suggest that lower levels of education and greater hostility are associated with greater "wear and tear" on the body. The effects of education on allostatic load may be mediated by hostility.

Adaptation, Physiological↗

PubMed1999

Relationship of lead in drinking water to bone lead levels twenty years later in Boston men: the Normative Aging Study.

Tap water in a city like Boston, which has old houses containing lead plumbing, is known to be a significant source of potential lead exposure. Bone lead levels integrate exposure over many years, and in vivo bone lead measurements have recently become possible with the advent of K x-ray fluorescence instruments. Thus we examined the relationship between first morning tap-water lead levels measured in homes in the 1970s and levels of lead in bone measured in the 1990s among middle-aged to elderly men who lived in those homes. We studied 129 participants in the Normative Aging Study who had lead measured in their homes' tap water in 1976 and 1977 by graphite furnace-atomic absorption spectrophotometry. From 1991 to 1995, the same subjects had blood lead levels measured by graphite furnace-atomic absorption spectroscopy and tibia and patella bone lead levels measured by K x-ray fluorescence. We ran multivariate linear regression models predicting bone lead levels that adjusted for factors which had previously been linked with this outcome in the Normative Aging Study (age, pack-years of smoking, and educational level). Among subjects who lived in houses with > or = 50 micrograms lead/liter of first morning tap water representing water that had been standing overnight in the plumbing in 1976 and 1977, those who reported medium or high levels of tap-water ingestion (> or = 1 glass/day) had progressively higher patella lead levels than did those with low levels of ingestion (< 1 glass/day). No such relationship was found among subjects who lived in houses with < 50 micrograms lead/liter of first morning tap water in 1976 and 1977. We conclude that ingestion of lead-contaminated tap water is an important predictor of elevated bone lead levels later in life.

Adult↗

PubMed1999

The FEF25-75/FVC ratio is associated with methacholine airway responsiveness. The normative aging study.

Airway responsiveness is known to be partly explained by geometric and anatomic factors. This cross-sectional investigation was undertaken to determine whether FEF25-75/FVC as a surrogate measure of airway size relative to lung size is associated with airway responsiveness to methacholine. Posteroanterior chest radiographs and spirometry were performed on a group of 929 middle aged and older men from an ongoing longitudinal study, the Normative Aging Study, who returned for their regularly scheduled examination between 1984 and 1989. Subjects had a mean age of 60.5 +/- 7.7 yr. FEV1, FEF25-75, and FVC were taken from spirometric results and FEF25-75/FVC ratios were obtained. Main bronchus (MB) and tracheal (TR) diameters and lung area (LA) were obtained from chest radiographs, and ratios of MB/LA and TR/LA were calculated for each subject and compared with FEF25-75/ FVC as measures of airway size relative to lung size. In a multiple linear regression model adjusting for age, height, initial FEV1, smoking, eosinophil count, and IgE level, FEF25-75/FVC was significantly related to the degree of methacholine airway responsiveness as measured by Log10 dose response slope (beta = -0.37, p < 0.001). Controlling for the same variables, both MB/LA (beta = -149.07, p < 0.001) and TR/LA (beta = -125.87, p < 0.001) were significant predictors of the degree of bronchial responsiveness in separate regression models; however, their effects were greatly attenuated when FEF25-75/ FVC was present in the same model. Similar results were obtained after excluding subjects with FEV1/ FVC </= 0.70 and subjects who had any smoking history. We conclude that FEF25-75/FVC as a surrogate measure of airway size relative to lung size is significantly associated with airway responsiveness.

Adult↗

PubMed1999

The independent contribution of bone and erythrocyte lead to urinary lead among middle-aged and elderly men: the normative aging study.

Plasma is the component of blood from which lead is free to cross cell membranes and cause organ toxicity. Plasma lead levels, however, are extremely low and difficult to measure. Urinary lead originates from plasma lead that has been filtered at the glomerular level; thus, urinary lead adjusted for glomerular filtration rate serves as a proxy for plasma lead levels. In this investigation we examined the interrelationships of lead levels in whole blood corrected by hematocrit [i.e., erythrocyte lead (EPb)], trabecular bone (TBoPb), cortical bone (CBoPb), and urine excreted over 24 hr (UPb); all samples were obtained from 71 middle-aged and elderly men with no known occupational lead exposures. Lead was measured by graphite furnace atomic absorption spectroscopy (blood), K-X-ray fluorescence (bone), and inductively coupled plasma mass spectroscopy (urine). Lead levels were generally low, with mean EPb, TBoPb, and CBoPb values of 13.8, 31.1, and 21.7 microg/g, respectively, and a median UPb value of 6.15 microg/day. In generalized additive models adjusted for body weight and creatinine clearance rate, both EPb and bone lead variables remained independently and significantly associated with UPb. This finding suggests that bone influences plasma lead in a manner that is independent of the influence of erythrocytic lead on plasma lead. Thus, the superiority of bone lead over blood lead in predicting some chronic forms of toxicity may be mediated through bone's influence on plasma lead. In addition, this study suggests that measurement of urinary lead might be useful as a proxy for plasma lead levels in studies of lead toxicity.

Aged↗

PubMed1998

Depression and the risk of coronary heart disease in the Normative Aging Study.

Increasing evidence supports an association between symptomatic depression and the risk of coronary heart disease (CHD), although no single study has compared multiple depression scales. We hypothesized that higher levels of symptomatic depression assessed from different depression scales were associated with the risk of CHD. We examined this relation in the Normative Aging Study, a prospective cohort of older men. A total of 1,305 men free of diagnosed CHD in 1986 completed the revised Minnesota Multiphasic Personality Inventory (MMPI-2). We categorized scores for the MMPI-2 D, MMPI-2 DEP, and Symptom Checklist-90 (SCL-90) depression scales. During an average 7.0 years of follow-up, 110 cases of incident CHD occurred, including 30 cases of nonfatal myocardial infarction, 20 cases of fatal CHD, and 60 cases of angina pectoris. Compared with men reporting the lowest level of depression, men in the highest level of depression had multivariate-adjusted relative risks of incident CHD (total CHD and angina) of 1.46 (95% confidence interval 0.83 to 2.57), 2.07 (95% confidence interval 1.13 to 3.81), and 1.73 (95% confidence interval 0.97 to 3.10) for the MMPI-2 D, MMPI-2 DEP, and SCL-90 scales, respectively. Similar RRs were obtained for each CHD subtype according to each depression scale. We found strong dose-response relations between level of depression measured by the MMPI-2 DEP scale and incidence of both angina pectoris (p value for trend, 0.039) and CHD (p value for trend, 0.016). Among older men, symptomatic depression measured by any of 3 depression scales may be positively associated with the risk of CHD.

Aging↗

PubMed1998

Prospective study of a self-report type A scale and risk of coronary heart disease: test of the MMPI-2 type A scale.

BACKGROUND: Several methods exist by which to assess type A behavior (TAB). Although the videotaped clinical interview is regarded as the "gold standard," self-report measures have also proved useful in assessing TAB in large population studies. The purpose of this study was to examine prospectively the relationship of TAB to risk of coronary heart disease (CHD) incidence with the use of the revised Minnesota Multiphasic Personality Inventory (MMPI-2) Type A Scale. To the best of our knowledge, this is the first test of this scale in the context of predicting CHD incidence. METHODS AND RESULTS: The study was performed in the VA Normative Aging Study, an ongoing cohort of older (mean age, 61 years) community-dwelling men. A total of 1305 men who were free of diagnosed CHD in 1986 completed the MMPI-2 Type A Scale. During an average 7.0 years of follow-up, 110 cases of incident CHD occurred. Compared with men in the lowest quartile of type A scores, men in the highest quartile had multivariate adjusted relative risks of 2.86 (95% CI, 1.19 to 6.89; P for trend=0.016) for combined CHD death and nonfatal myocardial infarction (MI) and 2.30 (95% CI, 1.32 to 4.01; P for trend=0.001) for combined CHD death/nonfatal MI plus angina pectoris. The relationship of TAB to CHD was independent of measures of anger and cynicism. CONCLUSIONS: The MMPI-2 Type A Scale predicts CHD incidence. Further research is warranted to examine the correlation, if any, between this scale and the videotaped clinical interview.

Adult↗

PubMed1998

Relation of nutrition to bone lead and blood lead levels in middle-aged to elderly men. The Normative Aging Study.

The relations of nutritional factors to lead accumulation in the body were examined cross-sectionally among 747 men aged 49-93 years (mean 67 years) in the Normative Aging Study in 1991-1995. Means (standard deviations) for blood lead, tibia lead, and patella lead were 6.2 (4.1) microg/dl, 21.9 (13.3) microg/g, and 32.0 (19.5) microg/g, respectively. In multiple regression models adjusting for age, education level, smoking, and alcohol consumption, men in the lowest quintile of total dietary intake levels of vitamin D (including vitamin supplements) (<179 i.u./day) had mean tibia and patella lead levels 5.6 microg/g and 6.0 microg/g higher than men with intake in the highest quintile (> or =589 i.u./day). Higher calcium intake was associated with lower bone lead levels, but this relation became insignificant when adjustment was made for vitamin D. The authors also observed inverse associations of blood lead levels with total dietary intake of vitamin C and iron. When analyses were controlled for patella lead, age, smoking, and alcohol consumption, men in the lowest vitamin C intake quintile (<109 mg/day) had a mean blood lead level 1.7 microg/dl higher than men in the highest quintile (> or =339 mg/day), while men in the lowest iron intake quintile (<10.9 mg/day) had a mean blood lead level 1.1 microg/dl higher than men in the highest quintile (> or =23.5 mg/day). This study suggests that low dietary intake of vitamin D may increase lead accumulation in bones, while lower dietary intake of vitamin C and iron may increase lead levels in the blood.

Aged↗

PubMed1998

Temporal relations between obesity and insulin: longitudinal data from the Normative Aging Study.

Although obesity and insulin levels are generally associated in cross-sectional data, the temporal and causal nature of their association is not yet clear. Increased obesity may have preceded increased insulin levels or vice versa. The authors examined the temporal relations between fasting insulin blood levels and weight in longitudinal data from the ongoing Normative Aging Study. Two insulin measurements from which a rate of change (delta Insulin) could be calculated were available from 376 non-diabetic male subjects (mean age = 62.1 years). Rate of change in weight could be calculated for the previous inter-examination period (delta Weight1), the contemporaneous period (delta Weight2), and the inter-examination period following the second insulin measurement (delta Weight3). delta Weight2 was a significant predictor (p = 0.0005) of delta insulin in multiple linear regression models that included control for potential confounders (body mass index, waist-to-hip ratio, antihypertensive and diuretic medication use, and age) and for correlation between the initial level and change in insulin (mean fasting insulin). delta Weight1 was added to the model and was found not to be statistically significant (p = 0.15). When the model was stratified by age tertile, the regression coefficient on delta Weight1 was -0.44 (p = 0.018) for the youngest stratum, -0.06 (p = 0.72) for the middle stratum, and 0.21 (p = 0.19) for the oldest men. Similarly, delta Insulin was a significant predictor of delta Weight3 (p = 0.026) in a separate regression model. These findings are consistent with both possible temporal sequences of association between changes in insulin and obesity. The intricate homeostatic mechanisms that regulate changes in insulin and obesity may not be readily amenable to description in terms of cause and effect.

Aged↗