Biomedical subjects

Deborah A Jones

Publications and source records attributed to Deborah A Jones.

8 recordsLinked to original sources

PubMed2007

Race/ethnicity, social class, and leisure-time physical inactivity.

PURPOSE: The aims of this study were to determine 1) prevalence of leisure-time physical inactivity in a nationally representative sample of non-Hispanic white, non-Hispanic black, and Hispanic men and women; 2) prevalence of leisure-time inactivity by racial/ethnic group across social class indicators; and 3) the relationship between leisure-time inactivity and occupational physical activity, independent of other social class indicators. METHODS: The National Physical Activity and Weight Loss Survey was a telephone survey of noninstitutionalized U.S. adults (4695 men, 6516 women) conducted by random digit dialing between September and December 2002. Self-reported physical activity was assessed using questions from the 2001 Behavioral Risk Factor Surveillance System. Respondents who reported no moderate- or vigorous-intensity physical activity during leisure time in a usual week were classified as inactive. Indicators of social class were education, family income, employment status, and marital status. RESULTS: Age-adjusted prevalence of leisure-time inactivity was 9.9% +/- 0.6 SE (standard error) and 12.0 +/- 0.6 for white men and women, respectively; 19.0 +/- 2.5 and 25.2 +/- 2.1 for non-Hispanic black men and women, and 20.9 +/- 2.1 and 27.3 +/- 2.5 for Hispanic men and women. Within each racial/ethnic group, prevalence of leisure-time inactivity was highest among participants of lower social class. Differences in inactivity by racial/ethnic group were less evident after adjustment for social class. Odds of inactivity were similar across quartiles of occupational physical activity after adjustment for age, sex, and social class. CONCLUSIONS: Non-Hispanic blacks and Hispanics were more inactive during their leisure time than were non-Hispanic whites. Social class but not occupational physical activity seems to moderate the relationship between race/ethnicity and leisure-time physical inactivity.

Adolescent↗

PubMed2006

Comparison of the 2001 BRFSS and the IPAQ Physical Activity Questionnaires.

PURPOSE: The 2001 Behavioral Risk Factor Surveillance System (BRFSS) physical activity module and the International Physical Activity Questionnaire (IPAQ) are used in population studies to determine the prevalence of physical activity. The comparability of the prevalence estimates has not been compared in U.S. adults. This study compares the physical activity prevalence estimates from the BRFSS and the IPAQ. METHODS: A telephone survey was administered to a random sample of 11,211 U.S. adults aged 18-99 yr who were enrolled in the National Physical Activity and Weight Loss Survey. Data were analyzed from 9945 adults who provided complete data on the BRFSS and the IPAQ. Prevalence estimates were computed (1) applying the BRFSS scoring scheme for both questionnaires (2). Kappa statistics were used to compare prevalence estimates generated from the BRFSS and the IPAQ. RESULTS: When scored using the BRFSS protocol, agreement between physical activity categories was fair (kappa = 0.34-0.49). Prevalence estimates were higher on the IPAQ than the BRFSS for the lowest category (inactive) by 0.1-3.9% and for the highest category (meets recommendations) by 0.2-9.7%. When scored using their own scoring, agreement between physical activity categories was lower (kappa = 0.26-0.39). The prevalence estimates on the IPAQ were higher than on the BRFSS for the lowest physical activity category by 0.2-13.3% and for the highest physical activity category by 0-16.4%. Differences in physical activity categories were observed for sex, age, income, education, and body mass index on both questionnaires. CONCLUSION: Because of differences in the physical activity prevalence estimates, direct comparison of the BRFSS and IPAQ prevalence estimates is not recommended.

Adolescent↗

PubMed2005

Prevalence of physical activity in the United States: Behavioral Risk Factor Surveillance System, 2001.

INTRODUCTION: The health benefits of regular cardiovascular exercise are well-known. Such exercise, however, has traditionally been defined as vigorous physical activity, such as jogging, swimming, or aerobic dance. Exercise of moderate intensity also promotes health, and many U.S. adults may be experiencing the health benefits of exercise through lifestyle activities of moderate intensity, such as yard work, housework, or walking for transportation. Until recently, public health surveillance systems have not included assessments of this type of physical activity, focusing on exercise of vigorous intensity. We used an enhanced surveillance tool to describe the prevalence and amount of both moderate-intensity and vigorous-intensity physical activity among U.S. adults. METHODS: We analyzed data from the 2001 Behavioral Risk Factor Surveillance System, a state-based, random-digit-dialed telephone survey administered to U.S. adults aged 18 years and older (n = 82,834 men and 120,286 women). Physical activity behavior was assessed using questions designed to quantify the frequency of participation in moderate- or vigorous-intensity physical activities performed during leisure time or for household chores and transportation. RESULTS: Overall, 45% of adults (48% of men and 43% of women) were active at recommended levels during nonworking hours (at least 30 minutes five or more days per week in moderate-intensity activities, equivalent to brisk walking, or at least 20 minutes three or more days per week in vigorous activities, equivalent to running, heavy yard work, or aerobic dance). Less than 16% of adults (15% of men and 17% of women) reported no moderate or vigorous activity in a usual week. CONCLUSION: Integrating surveillance of lifestyle activities into national systems is possible, and doing so may provide a more accurate representation of the prevalence of recommended levels of physical activity. These results, however, suggest that the majority of U.S. adults are not active at levels associated with the promotion and maintenance of health.

Adult↗

PubMed2005

Metabolism of the intervertebral disc: effects of low levels of oxygen, glucose, and pH on rates of energy metabolism of bovine nucleus pulposus cells.

STUDY DESIGN: In vitro measurements of metabolic rates of isolated bovine nucleus pulposus cells at varying levels of oxygen, glucose, and pH. OBJECTIVES: To obtain quantitative information on the interactions between oxygen and glucose concentrations and pH, and the rates of oxygen and glucose consumption and lactic acid production, for disc nucleus cells. SUMMARY OF BACKGROUND DATA: Disc cells depend on diffusion from blood vessels at the disc margins for supply of nutrients. Loss of supply is thought to lead to disc degeneration, but how loss of supply affects nutrient concentrations in the disc is not known; nutrient concentrations within discs can normally only be calculated, because concentration measurements are invasive. However, realistic predictions cannot be made until there are data from measurements of metabolic rates at conditions found in the disc in vivo, i.e., at low levels of oxygen, glucose, and pH. METHODS: A metabolism chamber was designed to allow simultaneous recording of oxygen and glucose concentrations and of pH. These concentrations were measured electrochemically with custom-built glucose and oxygen sensors; lactic acid was measured biochemically. Bovine nucleus pulposus cells were isolated and inserted into the chamber, and simultaneous rates of oxygen and glucose consumption and of lactic acid production were measured over a range of glucose, oxygen, and pH levels. RESULTS: There were strong interactions between rates of metabolism and oxygen consumption and pH. At atmospheric oxygen levels, oxygen consumption rate at pH 6.2 was 32% of that at pH 7.4. The rate fell by 60% as oxygen concentration was decreased from 21 to 5% at pH 7.4, but only by 20% at pH 6.2. Similar interactions were seen for lactic acid production and glucose consumption rates; we found that glycolysis rates fell at low oxygen and glucose concentrations and low pH. Equations were derived that satisfactorily predict the effect of nutrient and metabolite concentrations on rates of lactic acid production rate and oxygen consumption. CONCLUSIONS: Disc cell metabolism in air and at pH 7.4 differs markedly from that found in the disc nucleus in vivo, where low levels of oxygen, glucose, and pH all coexist.

Animals↗

PubMed2005

Total and leisure-time walking among U.S. adults should every step count?

BACKGROUND: Although walking is a popular leisure-time activity, a substantial amount of total daily walking occurs in non-leisure contexts (i.e., occupation, transportation, and household work). Because non-leisure walking is not assessed by traditional leisure-time activity surveys, total walking among U.S. adults may be underestimated. This study describes walking estimates obtained from a measure of leisure-time activity and a specific measure of total walking in all contexts. METHODS: A national sample of adults (n=6626), selected by random-digit dialing, was surveyed between May 1999 and November 2000. Estimates of walking prevalence and of weekly time spent walking were examined from two separate modules: (1) an assessment restricted to leisure-time activity, and (2) an assessment of total walking. RESULTS: Walking prevalence based on the total walking module was nearly double that based on the leisure-time module (81% vs 43%, respectively). The median weekly minutes of walking also nearly doubled using the total walking module (239 vs 130 minutes, respectively). Among those with jobs involving substantial walking, median weekly walking minutes were more than three times greater with the total walking module (476 vs 130 minutes, respectively). CONCLUSIONS: U.S. adults, particularly those with jobs involving walking, do a substantial amount of walking not captured by traditional leisure-time activity surveys. This may affect the appropriate targeting of physical activity interventions, as well as the evaluation of the effectiveness of physical activity promotions and policies. However, further characterization of non-leisure walking is needed to determine its contribution to health and meeting physical activity guidelines.

Adolescent↗

PubMed2005

Dynamic changes in brain glucose and lactate in pericontusional areas of the human cerebral cortex, monitored with rapid sampling on-line microdialysis: relationship with depolarisation-like events.

The pathophysiology of peri-lesion boundary zones in acute brain injury is highly dynamic, and it is now clear that spreading-depression-like events occur frequently in areas of cerebral cortex adjacent to contusions in the injured human brain. An automated method to assay microdialysate from peri-lesion cerebral cortex in 11 patients with intracranial haematomas requiring surgery was used. Perfusate (2 microL/min) flowed directly into a flow-injection system for assay of glucose and lactate at intervals typically of 30 secs each. Four channels of electrocorticogram (ECoG) were recorded from a subdural strip adjacent to the catheter. Several patterns of change in metabolites were identified in different time domains. Overall, the number of transient lactate events was significantly correlated with the number of glucose events (r2=0.48, P=0.027, n=10). Progressive reduction in dialysate glucose was very closely correlated with the aggregate number of ECoG events (r2=0.76, P=0.0004, n=11). It is proposed that the recently documented adverse impact of low dialysate glucose on clinical outcome may be because of recurrent, spontaneous spreading-depression-like events in the perilesion cortex.

Adult↗

PubMed2004

Attempting to lose weight: specific practices among U.S. adults.

BACKGROUND: Americans spend over $33 billion annually on weight-loss products and services. Although weight-control methods are of considerable public health interest, few national data on weight-loss practices are available. This paper examines the prevalence of specific weight-loss practices among U.S. adults trying to lose weight. METHODS: Data from the 1998 National Health Interview Survey, which was conducted through face-to-face interviews of a nationally representative sample of U.S. adults (n =32,440), were analyzed in 2003. RESULTS: Twenty-four percent of men and 38% of women were trying to lose weight. Attempting weight loss was less common among normal weight (body mass index [BMI]<25 kg/m(2)) people (6% men, 24% women) than overweight (BMI>/=25 to 30 kg/m(2)) people (28%, 49%) or obese (BMI>/=30 kg/m(2)) people (50%, 58%). Among those trying to lose weight, the most common strategies were eating fewer calories (58% men, 63% women); eating less fat (49%, 56%); and exercising more (54%, 52%). Less frequent strategies were skipping meals (11% men, 9% women); eating food supplements (5%, 6%); joining a weight-loss program (3%, 5%); taking diet pills (2%, 3%); taking water pills or diuretics (1%, 2%); or fasting for >/=24 hours (0.6%, 0.7%). Only one third of all those trying to lose weight reported eating fewer calories and exercising more. CONCLUSIONS: Increased efforts are needed among all those trying to lose weight to promote effective strategies for weight loss, including the use of calorie reduction and increased physical activity.

Adolescent↗

PubMed2003

Ambulatory activity and simple cardiorespiratory parameters at rest and submaximal exercise.

The purpose of this study was to explore the relationship between objectively determined ambulatory activity and simple cardiorespiratory parameters (heart rate and blood pressure at rest and during submaximal exercise) in individuals who were stratified for self-reported participation (yes/any vs. no/none) in vigorous physical activity (PA). Ninety-eight subjects (African Americans: 7 M, 16 F; Caucasians: 33 M, 42 F; mean age 46.4 +/- 15.4 yrs; mean BMI 26.7 +/- 4.8) wore a pedometer for 21 consecutive days and completed a 10-min submaximal treadmill graded exercise test with HR (beats/min) and BP (mmHg) measured while walking at 4.8 km/hr and a 10% grade. Subjects averaged 7,618 +/- 3.045 steps/day. There were no differences in steps/day by self-reported vigorous PA strata. There was an inverse relationship (r = -0.35, p = 0.03) between steps/day and resting HR in subjects who reported no vigorous PA. There was an inverse relationship (r = -0.22, p = 0.04) between steps/day and submaximal HR in all subjects. When stratified for self-reported vigorous PA, the inverse relationship between steps/day and submaximal HR was stronger for those reporting no vigorous PA (r = -0.39, p = 0.01) vs. those reporting any vigorous PA (r = -0.28, p = 0.05). There was no relationship between steps/day and BP at rest or during exercise in this normotensive sample.

Adolescent↗