Smoking, physical activity, and active life expectancy.
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Aged↗
Biomedical subjects
I M Lee
Publications and source records attributed to I M Lee.
Exercise and risk of stroke in male physicians.
BACKGROUND AND PURPOSE: From a physiological perspective, physical activity might be expected to decrease the risk of developing stroke. However, epidemiological studies of physical activity and stroke risk have yielded divergent findings. We therefore sought to examine the association between exercise and stroke risk. METHODS: This was a prospective cohort study of 21 823 men, followed up for an average of 11.1 years. Participants were from the Physicians' Health Study, a randomized trial of low-dose aspirin and beta carotene. Men, aged 40 to 84 years at baseline, were free of self-reported myocardial infarction, stroke, transient ischemic attack, and cancer. At baseline, they reported on the frequency of exercise vigorous enough to work up a sweat. Stroke occurrence was reported by participants and confirmed after medical record review (n=533). We used Cox proportional hazards regression to analyze the data. RESULTS: With adjustment for age, treatment assignment, smoking, alcohol intake, history of angina, and parental history of myocardial infarction, the relative risks of total stroke associated with vigorous exercise <1 time, 1 time, 2 to 4 times, and >/=5 times per week at baseline were 1.00 (referent), 0.79 (95% confidence interval [CI], 0.61 to 1. 03), 0.80 (95% CI, 0.65 to 0.99), and 0.79 (95% CI, 0.61 to 1.03), respectively; P for trend=0.04. In subgroup analyses, the inverse association appeared stronger with hemorrhagic than ischemic stroke. When we additionally adjusted for body mass index, history of hypertension, high cholesterol, and diabetes mellitus, corresponding relative risks for total stroke were 1.00 (referent), 0.81 (95% CI, 0.61 to 1.07), 0.88 (95% CI, 0.70 to 1.10), and 0.86 (95% CI, 0.65 to 1.13), respectively; P for trend=0.25. CONCLUSIONS: Exercise vigorous enough to work up a sweat is associated with decreased stroke risk in men. In the present study, the inverse association with physical activity appeared to be mediated through beneficial effects on body weight, blood pressure, serum cholesterol, and glucose tolerance. Apart from its favorable influences on these variables, physical activity had no significant residual association with stroke incidence.
Adult↗
Aspirin use and colorectal cancer: post-trial follow-up data from the Physicians' Health Study.
BACKGROUND: In contrast to most observational studies, the randomized Physicians' Health Study found no association between aspirin use and colorectal cancer after 5 years. OBJECTIVE: To determine the effect of randomly assigned aspirin treatment and self-selected aspirin use on the incidence of colorectal cancer after 12 years and to identify factors influencing the self-selection of regular aspirin use. DESIGN: Randomized clinical trial and prospective cohort study. SETTING: Male physicians throughout the United States. PATIENTS: 22071 healthy male physicians who were 40 to 84 years of age in 1982. INTERVENTION: 325 mg of aspirin every other day. In 1988, the aspirin arm of the randomized trial was stopped early. Participants then chose to receive either aspirin or placebo for the rest of the study. MEASUREMENTS: Annual questionnaires asking about aspirin use and other variables, including occurrence of cancer. RESULTS: Colorectal cancer was diagnosed in 341 patients during the study period. Over 12 years of follow-up, random assignment to aspirin was associated with a relative risk for colorectal cancer of 1.03 (95% CI, 0.83 to 1.28). Various gastrointestinal symptoms and diagnoses were strong predictors of less frequent aspirin use in 1988. The relative risk for colorectal cancer in persons who used aspirin frequently after 1988 was 1.07 (CI, 0.75 to 1.53). CONCLUSIONS: In the Physicians' Health Study, both randomized and observational analyses indicate that there is no association between the use of aspirin and the incidence of colorectal cancer. The low dose of aspirin used and the short treatment period may account for the null findings. However, other characteristics associated with the use of aspirin in observational studies remain a plausible alternative explanation.
Adult↗
Body mass index, cigarette smoking, and other characteristics as predictors of self-reported, physician-diagnosed gallbladder disease in male college alumni.
Despite the high prevalence of gallbladder disease in industrialized countries, little is known about the predictors of the disease, especially in men. The authors prospectively studied 16,785 alumni of Harvard University, aged 15-24 years, who were followed for up to 61 years. The health characteristics of these men were ascertained from their college entrance physical examination done in 1916-1950, and updated via mailed questionnaires in 1962 or 1966 (1962/1966). Alumni subsequently self-reported physician-diagnosed gallbladder disease on further mailed questionnaires in 1972 or 1977. Between college time and 1962/1966, 371 gallbladder disease cases occurred. An additional 314 cases occurred after 1962/1966. With respect to college characteristics, after adjustment for potential confounders, the authors found that body mass index (BMI), smoking, physical activity, blood pressure, and consumption of alcohol, coffee, or tea were unrelated to risk. However, BMI in 1962/1966 was directly related to risk of subsequent gallbladder disease, as was BMI gain since college (p, trend = 0.002 and 0.013, respectively). Compared with men with BMI < 22.0, men with BMI > or = 27.0 had a rate ratio of 2.71 (95% confidence interval (CI) 1.57-4.66) for risk of contracting the disease. Men who gained > or = 6.0 BMI units since college had a rate ratio of 1.46 (95% CI 0.86-2.46) compared with men who gained -0.9 to +0.9 BMI units. Compared with never smokers, men who smoked pipes or cigars or < 1 pack of cigarettes daily in 1962/1966 had a rate ratio of 1.43 (95% CI 1.00-2.06), while heavier cigarette smokers had a rate ratio of 1.52 (95% CI 1.03-2.24). Neither physical activity nor physician-diagnosed hypertension or diabetes mellitus in 1962/1966 predicted risk.
Adolescent↗
Physical activity and breast cancer risk in the College Alumni Health Study (United States).
OBJECTIVES: It is unclear whether physical activity is associated with a reduced risk of breast cancer. Some studies also suggest different effects between pre- and postmenopausal women, and lean and heavy women. METHODS: We followed 1,566 University of Pennsylvania alumnae (mean age, 45.5 years), initially free of breast cancer, from 1962 until 1993. Physical activity at baseline was assessed by asking women about stairs climbed, blocks walked, and sports played. We estimated energy expenditure and categorized women into approximate thirds (< 500, 500-999, 1,000+ kcal/wk). We identified 109 breast cancer cases during 35,365 person-years from follow-up questionnaires or from death certificates. RESULTS: After adjustment for age and body mass index (BMI) (kg/m2), the relative risk (RR) of breast cancer was 0.92 (95 percent confidence interval [CI] = 0.58-1.45) among women expending 500-999 kcal/wk and 0.73 (CI = 0.46-1.14) for those expending 1,000+ kcal/wk, compared with women expending < 500 kcal/wk (P trend = 0.17). This association was modified by menopausal status, but not BMI. For postmenopausal women, corresponding RRs were 0.95 (CI = 0.58-1.57) and 0.49 (CI = 0.28-0.86), respectively (P trend = 0.015). Increased physical activity in premenopausal women was not significantly associated with decreased risk of breast cancer. CONCLUSIONS: These data support an inverse association between physical activity and breast cancer among postmenopausal women.
Adult↗
Body weight and mortality: what is the shape of the curve?
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Adult↗
Physical activity and stroke incidence: the Harvard Alumni Health Study.
BACKGROUND AND PURPOSE: Physiologically, it appears plausible for physical activity to decrease stroke risk; however, epidemiological studies have produced mixed findings. Furthermore, few studies have examined specific kinds and intensities of activities. The purpose of this study was to examine the association between physical activity, including its various components (walking, climbing stairs, participation in sports and recreational activities), and stroke risk. METHODS: This was a prospective cohort study of 11 130 Harvard University alumni (mean age, 58 years) without cardiovascular disease and cancer at baseline. Men reported their walking, stair climbing, and participation in sports or recreation on baseline questionnaires in 1977. Stroke occurrence was assessed with another questionnaire in 1988. Death certificates were obtained for decedents through 1990 to determine strokes not previously reported (total strokes=378). We used Cox proportional hazards regression to estimate the relative risks and 95% CIs for stroke occurrence associated with physical activity. RESULTS: After adjustment for age, smoking, alcohol intake, and early parental death, the relative risks of stroke associated with <1000, 1000 to 1999, 2000 to 2999, 3000 to 3999, and >/=4000 kcal/wk of energy expenditure at baseline were 1.00 (referent), 0.76 (95% CI, 0.59 to 0.98), 0.54 (0.38 to 0. 76), 0.78 (0.53 to 1.15), and 0.82 (0.58 to 1.14), respectively; P=0. 05 for linear trend. Walking >/=20 km/wk was associated with significantly lower risk, independent of other physical activity components. Climbing stairs and activities of at least moderate intensity (>/=4.5 METs, or multiples of resting metabolic rate) each showed U-shaped relations to stroke risk, with the risk being significantly lower at the nadir of the curve. Light intensity activities (<4.5 METs), however, were unrelated to stroke risk. CONCLUSIONS: Physical activity is associated with decreased stroke risk in men. A decreased risk was observed at energy expenditures of 1000 to 1999 kcal/wk, with further risk decrement seen at 2000 to 2999 kcal/wk but not beyond. Confirmation of the U-shaped relation observed in these data requires similar observations in other populations.
Aged↗
Physical activity and risk of colon cancer: the Physicians' Health Study (United States).
Previous studies indicate that physical activity is related inversely to colon cancer risk. However, details regarding that association--whether a dose-response relation exists, whether the relation differs between non-obese and obese persons, the effect of long-term physical activity--are unclear. We examined these issues in the Physicians' Health Study (United States). Physical activity was assessed at baseline among 21,807 men, aged 40 to 84 years, and again 36 months later. Men were followed for an average of 10.9 years (from baseline) during which 217 developed colon cancer. After adjusting for potential confounders (including age, obesity, and alcohol intake), the relative risks for colon cancer associated with vigorous exercise in times per week (< 1, 1, 2-4, 5+, at baseline) were 1.0 (referent); 1.1 (95% confidence interval [CI] = 0.7-1.7); 1.2 (CI = 0.8-1.6); and 1.1 (CI = 0.7-1.6), respectively; P trend = 0.6. Physical activity was not associated significantly with colon cancer risk either among non-obese or obese men. When we used physical activity assessments at baseline as well as at 36 months, physical activity again was unrelated to colon cancer risk. These data do not support the hypothesis that physical activity reduces the risk of colon cancer. Plausible alternate explanations for the null finding include misclassification of physical activity and the potential for increased surveillance for colon cancer ('screening effect') among those physically active.
Adult↗
Adult height and incidence of cancer in male physicians (United States).
Adult height has been found in some but not all studies to be associated positively with overall cancer incidence as well as several site-specific cancers. The Physicians' Health Study (PHS), a randomized trial of beta-carotene and aspirin in the primary prevention of cancer and cardiovascular disease in men, provided an opportunity to examine the association between height and total malignant neoplasms (excluding non-melanoma skin cancer), as well as site-specific cancers including prostate, colorectal, and lung cancer. The PHS is comprised of 22,071 US male physicians in the United States, a population homogeneous for adult socioeconomic status, aged 40 to 84 years in 1982. Participants were classified into five height categories at study entry. After an average follow-up of over 12 years, there were 2,566 cases of incident total malignant neoplasms, including 1,047 prostate, 341 colorectal, and 170 lung cancer cases. Height was associated positively with both total malignant neoplasms and prostate cancer. Compared with men in the shortest category (<67 inches), relative risks and 95 percent confidence intervals (CI) for total malignant neoplasms for men whose height (in inches) was 68-69, 70-71, 72, and 73+ were, respectively: 1.13 (CI = 0.99-1.28), 1.15 (CI = 1.02-1.30), 1.29 (CI = 1.12-1.49), and 1.21 (CI = 1.05-1.39), P trend 0.001, adjusted for age, randomized treatment assignments, body mass index (wt/ht2), cigarette smoking, alcohol use, and exercise frequency. For prostate cancer, the corresponding RR values were 1.23 (CI = 1.00-1.51), 1.26 (CI = 1.04-1.54), 1.59 (CI = 1.27-1.98), and 1.26 (CI = 1.00-1.59), P trend 0.005. For colorectal cancer, in some but not all height categories compared with the shortest, there were elevated RRs without a significant linear trend: RR = 1.51 (CI = 1.06-2.14), 1.14 (CI = 0.80-1.62), 1.19 (CI = 0.79-1.80), and 1.53 (CI = 1.04-2.25), P trend 0.23. In contrast, there was no evidence of an association of height with lung cancer. These data indicate a positive association between height and risk of total malignant neoplasms, as well as of prostate cancer and, possibly, colorectal cancer.
Adult↗
Phytoplasma induced free-branching in commercial poinsettia cultivars.
Free-branching poinsettia cultivars that produce numerous axillary shoots are essential for propagating desirable multi-flowered poinsettias (Euphorbia pulcherrima Wild. Klotz). For more than a decade, a biological agent has been suspected to cause free-branching in poinsettias. Attempts to identify the branching agent have failed. Isolation of the pathogen was accomplished using a living host and it was concluded that an unculturable phytoplasma is the cause of free-branching in poinsettias. This is the first reported example of a pathogenic phytoplasma as the causal agent of a desirable and economically important trait.
DNA, Ribosomal↗
Physical activity and health of college men: longitudinal observations.
The College Alumni Health Study has examined host and environmental characteristics in youth and adult life as they relate to subsequent development of specific chronic diseases. Campus archives have provided physical, psychological, and social data on some 57,500 men and women who were born between 1896 and 1934, and who entered Harvard College or the University of Pennsylvania between 1916 and 1950, generally at age 17-20 years. These college data have been studied subsequently to assess whether characteristics in youth predisposed students to chronic diseases (nonfatal and fatal) later in life. Follow-up questionnaires, mailed to alumni, generally aged 35-85 years, in the 1960s, 1970s, 1980s, and 1990s have provided mid-life information on the health status and health habits of survivors, and official death certificates have provided data on decedents. This information has been studied, in fashion similar to the college data, for personal characteristics and ways of living that influenced health and longevity of these middle-aged and elderly men. Longitudinal observations continue today, in search of causes of specific chronic diseases.
Adolescent↗
"Candidatus phytoplasma australiense," a new phytoplasma taxon associated with Australian grapevine yellows.
A phytoplasma was detected in naturally diseased 'Chardonnay' grapevines exhibiting symptoms of Australian grapevine yellows disease. The use of PCR designed to amplify phytoplasma DNA resulted in detection of phytoplasma DNA in all of the diseased plants examined; no phytoplasma DNA was detected in healthy seedling grapevines. The collective restriction fragment length polymorphism (RFLP) patterns of amplified 16S ribosomal DNA differed from the patterns described previously for other phytoplamas. On the basis of the RFLP patterns, Australian grapevine yellows phytoplasma was classified as a representative of a new subgroup, designated subgroup 16SrI-J, in phytoplasma 16S rRNA group 16SrI (aster yellows and related phytoplasmas). A phylogenetic analysis in which parsimony of 16S rRNA gene sequences from this and other group 16SrI phytoplasmas was used identified the Australian grapevine yellows phytoplasma as a member of a distinct subclade (subclade xii) in the phytoplasma clade of the class Mollicutes. A phylogenetic tree constructed on the basis of 16S rRNA gene sequences was consistent with the hypothesis that there was divergent evolution of Australian grapevine yellows phytoplasma and its closet known relative, European stolbur phytoplasma (subgroup 16SrI-G), from a common ancestor. The unique properties of the DNA from the Australian grapevine yellows phytoplasma clearly establish that it represents a new taxon, "Candidatus Phytoplasma australiense."
Base Sequence↗
Nested PCR for ultrasensitive detection of the potato ring rot bacterium, Clavibacter michiganensis subsp. sepedonicus.
Oligonucleotide primers derived from sequences of the 16S rRNA gene (CMR16F1, CMR16R1, CMR16F2, and CMR16R2) and insertion element IS1121 of Clavibacter michiganensis subsp. sepedonicus (CMSIF1, CMSIR1, CMSIF2, and CMISR2) were used in nested PCR to detect the potato ring rot bacterium C. michiganensis subsp. sepedonicus. Nested PCR with primer pair CMSIF1-CMSIR1 followed by primer pair CMSIF2-CMSIR2 specifically detected C. michiganensis subsp. sepedonicus, while nested PCR with CMR16F1-CMR16R1 followed by CMR16F2-CMR16R2 detected C. michiganensis subsp. sepedonicus and the other C. michiganensis subspecies. In the latter case, C. michiganensis subsp. sepedonicus can be differentiated from the other subspecies by restriction fragment length polymorphism (RFLP) analyses of the nested PCR products (16S rDNA sequences). The nested PCR assays developed in this work allow ultrasensitive detection of very low titers of C. michiganensis subsp. sepedonicus which may be present in symptomiess potato plants or tubers and which cannot be readily detected by direct PCR (single PCR amplification). RFLP analysis of PCR products provides for an unambiguous confirmation of the identify of C. michiganensis subsp. sepedonicus.
Actinomycetales↗
Phylogeny and classification of bacteria in the genera Clavibacter and Rathayibacter on the basis of 16s rRNA gene sequence analyses.
A phylogenetic analysis by parsimony of 16S rRNA gene sequences (16S rDNA) revealed that species and subspecies of Clavibacter and Rathayibacter form a discrete monophyletic clade, paraphyletic to Corynebacterium species. Within the Clavibacter-Rathayibacter clade, four major phylogenetic groups (subclades) with a total of 10 distinct taxa were recognized: (I) species C. michiganensis; (II) species C. xyli; (III) species R. iranicus and R. tritici; and (IV) species R. rathayi. The first three groups form a monophyletic cluster, paraphyletic to R. rathayi. On the basis of the phylogeny inferred, reclassification of members of Clavibacter-Rathayibacter group is proposed. A system for classification of taxa in Clavibacter and Rathayibacter was developed based on restriction fragment length polymorphism (RFLP) analysis of the PCR-amplified 16S rDNA sequences. The groups delineated on the basis of RFLP patterns of 16S rDNA coincided well with the subclades delineated on the basis of phylogeny. In contrast to previous classification systems, which are based primarily on phenotypic properties and are laborious, the RFLP analyses allow for rapid differentiation among species and subspecies in the two genera.
Actinomycetales↗
Physical activity in the prevention of non-insulin-dependent diabetes mellitus.
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Aged↗
Is exercise beneficial in the prevention of prostate cancer?
Prostate cancer is the most frequently diagnosed cancer in men. Exercise has been studied as an alterable risk factor that may reduce the incidence, morbidity and mortality due to this cancer. Epidemiological studies play an important role in assessing the relationship between physical activity and prostate cancer. Studies have attempted to estimate physical activity level by measuring time spent in sports, leisure or occupational activity. We identified 17 studies that assessed the effect of exercise on the development of prostate cancer. Although methodological limitations could be identified in most of the studies, 9 suggested that exercise may be beneficial in decreasing prostate cancer risk, while 5 were null providing no conclusive evidence and 3 actually showed an increased risk of prostate cancer with increased physical activity. The bulk of the evidence at this time does not seem to support an overwhelmingly beneficial effect of exercise on prostate cancer risk. Future studies need to investigate the frequency, intensity and duration of physical activity as well as the type of activity and period during a man's lifetime when exercise might be beneficial. It is reasonable to conclude that exercise may be a potential factor that can be modified to prevent prostate cancer and it seems prudent to recommend that all men become physically active.
Exercise↗
Exercise for women--how much pain for optimal gain?
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Amenorrhea↗
Self-reported breast implants and connective-tissue diseases in female health professionals. A retrospective cohort study.
OBJECTIVE: To evaluate the association of breast implants with connective-tissue diseases. DESIGN AND PARTICIPANTS: Retrospective cohort study of 395,543 female health professionals who completed mailed questionnaires for potential participation in the Women's Health Study. A total of 10,830 women reported breast implants and 11,805 reported connective-tissue diseases between 1962 and 1991. Cox proportional hazards regression models were used in analyses. MAIN OUTCOME MEASURE: Self-reported connective-tissue diseases. RESULTS: Compared with women who did not report breast implants, the relative risk (RR) of the combined end point of any connective-tissue disease among those who reported breast implants was 1.24 (95% confidence interval, 1.08 to 1.41, P = .0015). With respect to the individual diseases, the finding for other connective-tissue diseases (including mixed) was statistically significant (P = .017), the findings for rheumatoid arthritis, Sjogren's syndrome, dermatomyositis or polymyositis, or scleroderma were of borderline statistical significance (.05 < P < .10), and the finding for systemic lupus erythematosus was not statistically significant (P = .44). There were no clear trends in RR with increasing duration of breast implants. CONCLUSION: These self-reported data from female health professionals are compatible with prior reports from other cohort studies that exclude a large hazard, but do suggest small increased risks of connective-tissue diseases among women with breast implants. The very large sample size makes chance an unlikely explanation for the results, but bias due to differential overreporting of connective-tissue diseases or selective participation by affected women with breast implants remains a plausible alternative explanation. The major contribution of this and other observational analytic studies has been to exclude large risks of connective-tissue diseases following breast implants.
Adult↗