The epidemiology of dog walking: an unmet need for human and canine health

OBJECTIVE

To describe the prevalence of dog walking in New South Wales, and to identify potential health gains if more dogs were walked.

DESIGN

Cross-sectional analytical survey.

SETTING AND PARTICIPANTS

894 adults in NSW in 1998 (among the owners of approximately two million domestic dogs in NSW who were potential participants in dog-walking behaviours).

INTERVENTIONS

None yet.

MAIN OUTCOME MEASURES

Dog walking hours per week; other DogEpi concepts to illustrate the public health gains include the DAF (dog attributable fraction), and the BBR (benefits to bites ratio).

RESULTS

The response rate to the survey was 74%. 46% of households in NSW had a dog and, overall, dog owners walked 18 minutes per week more than non-dog owners. However, more than half of dog owners did not walk their dogs, and were less likely than non-owners to meet recommended levels of physical activity sufficient for health benefits. If all dog owners walked their dogs, substantial disease prevention and healthcare cost savings of $175 million per year might accrue.

CONCLUSIONS

There are potential benefits of dog walking for human health; currently, among dog owners, much of this benefit remains to be realised. There are also likely benefits for canine health. Dog walking should be promoted through national strategies recommending "Walkies for all by the year 2010".

Six-month observational study of prompted stair climbing

BACKGROUND

Despite strong evidence that prompts at the point of choice between escalators and stairs encourage stair use, the long-term effects of stair prompts have not yet been investigated. Presented here are the results of a 6-month observational study of prompted stair climbing.

METHODS

Escalator and adjacent stair use were monitored in a shopping mall in the Midlands region of the United Kingdom. Participants were coded for gender, age, and ethnicity. A 2-week baseline period was followed by a 12-week intervention using motivating messages on the stair risers. Follow-up data were also collected for 2 weeks immediately after the removal of the banners and 6 weeks later.

RESULTS

A total of 45,361 escalator/stair-choice observations were made. Stair use increased significantly during the intervention period and, when the banners were removed, remained higher than at baseline. There were also significant interactions with time across the different population groups.

CONCLUSIONS

The full public health benefits of increasing physical activity levels can only be realized if the activity is sustained. These results demonstrate that stair-riser banners can elicit a sustained increase in stair use and, even when the banners were withdrawn, overall stair use remained higher than at baseline.

[Questionnaire research of the participants in a large scale walking event Fukuoka City analysis of walking habits and related factors]

PURPOSE

We examined the walking habits of the participants in the 'AIREF Spring Walk' which was held on March 9, 1997 in the western suburb of Fukuoka City. The aim of this walking event was to motivate the citizens, especially sedentary people, to walk by providing them an opportunity to enjoy walking.

METHODS

The participants walked one of three distances (5 km, 10 km or 20 km) and answered anonymously a questionnaire immediately after finishing (100% response rare). The questionnaire items covered sex, age, district of residence, the distance of the walking course, the source of information on the event, experience of participating in other walking events in the past, and walking habits.

RESULTS

The participants of this event (n = 1,039, mean age 49.4 +/- 18.9 [SD] years) were characterized by high rates for females (67%), those aged < 50 years (42%), residents of Fukuoka City (89%), those who chose to walk the shorter courses of 5 or 10 km (74%), and those who took part in a walking event for the first time (61%). Information on the event was obtained through other people (32%) such as friends, acquaintances, members of community walking groups or other family members, leaflets (21%) placed in the Fukuoka Health Promotion Center and seven Fukuoka City public health centers; a newspaper published biweekly by the municipal government (13%); and direct mail (11%). For those attending the 5 km course, more participants learned about the event through other family members compared with the other two courses. Participants who answered that they walked regularly constituted 56% of those aged 20 years or older. The rates for regular walkers significantly increased with the older participants (p < 0.01) and those who chose longer courses (p < 0.001). Compared with the regular walkers, those without a walking habit tended to have acquired information on the event from friends, acquaintances or other family members, or at their work sites (35%). The average amount of time spent was 249 +/- 175 min/week (n = 375). As a whole, only 30% of the participants aged 20 years or older walked longer than the amount of time for aerobic exercise recommended by the Health, Labor and Welfare Ministry (HLWM). The rate for those who reached the HLWM recommendations was increased in older subject (p < 0.001).

CONCLUSIONS

It is concluded that the aim of the walking event was partly accomplished, which was reflected by the relatively high rates of participation sedentary for people, compared with other large walking events. The sedentary participants tended to choose the relatively short distances and obtain the information about the event through other people. Walking promotion programs should be developed to motivate sedentary citizens to walk. The programs should also support regular walkers, many of whom are 50 years old or older, to maintain walking habits with the HLWM recommendations on aerobic exercise.

Reliability, validity, and responsiveness of the six-minute walk test in patients with heart failure

BACKGROUND

Our purpose was to evaluate the reliability, validity, and responsiveness of the 6-minute walk test (6MWT) in patients with heart failure (HF) enrolled in the Randomized Evaluation of Strategies for Left Ventricular Dysfunction (RESOLVD) pilot study.

METHODS

A total of 768 patients was enrolled in a multicenter randomized clinical trial evaluating the effect of candesartan, enalapril, and metoprolol on left ventricular ejection fraction (LVEF), 6MWT distance, neurohormones, and quality of life. The 6MWT was performed once at screening and twice at baseline, 18 weeks, and 43 weeks by a standardized method.

RESULTS

Test-retest reliability at baseline (intraclass correlation coefficient [ICC] = 0.90), 18 weeks (ICC = 0.88), and 43 weeks (ICC = 0.91) was very good. Baseline 6MWT distance was weakly inversely correlated to the quality-of-life cumulative score (r = -0.26, P =.0001) and moderately inversely correlated to the New York Heart Association functional classification (NYHA-FC) (r = -0.43, P =.001). In the RESOLVD study, the 6MWT was not responsive to change when effect sizes and standardized response means were used. Disease-specific quality of life was responsive to change in patients treated with candesartan and enalapril and NYHA-FC was responsive to change in the candesartan and enalapril combination and for enalapril alone with small effect sizes. The 6MWT, NYHA-FC, and quality of life were not responsive to change during the metoprolol or placebo phase.

CONCLUSIONS

The 6MWT is highly reproducible in patients with symptoms of HF. It is somewhat correlated to NYHA-FC and quality of life. Overall, quality of life was most responsive to change, whereas 6MWT and NYHA-FC were comparable but less responsive to change in the RESOLVD study.

Chronic obstructive pulmonary disease stage and 6-minute walk outcome

PURPOSE

Although physicians generally reserve pulmonary rehabilitation (PR) referral for patients in later stages of chronic obstructive pulmonary disease (COPD), there is no evidence to suggest that PR programs are more effective for these persons than for those in earlier stages of the disease. This study examined the relationship between 6-minute walk change and COPD stage in patients completing PR.

METHODS

The sample consisted of 76 patients who enrolled in the University of Alabama at Birmingham's Cardiopulmonary Rehabilitation Program with a primary diagnosis of COPD between January 1996 and June 2000. Data was collected on 6-minute walk upon entry into the program and upon program completion. Patients were stratified according to COPD stage using the American Thoracic Society staging system.

RESULTS

There were significant differences among the three stages with regard to initial and ending 6-minute walk distances such that persons in later stages of the disease have shorter initial and ending 6-minute walk distances. However, all three stages show significant improvements in the 6-minute walk after PR. There were no significant differences in the median change among groups indicating that the median change was not better (or worse) for patients in any particular COPD stage.

CONCLUSIONS

This study suggests that PR is equally effective in increasing physical performance for all patients regardless of COPD stage. This type of information can be used to support the recommendation of PR for patients early in the disease process.

Mobility difficulties are not only a problem of old age

BACKGROUND

Lower extremity mobility difficulties often result from common medical conditions and can disrupt both physical and emotional well-being.

OBJECTIVES

To assess the national prevalence of mobility difficulties among noninstitutionalized adults and to examine associations with demographic characteristics and other physical and mental health problems.

DESIGN

Cross-sectional survey using the 1994-1995 National Health Interview Survey-Disability Supplement (NHIS-D). We constructed measures of minor, moderate, and major lower extremity mobility difficulties using questions about ability to walk, climb stairs, and stand, and use of mobility aids (e.g., canes, wheelchairs). Age and gender adjustment used direct standardization methods in Software for the Statistical Analysis of Correlated Data (SUDAAN).

PARTICIPANTS

Noninstitutionalized, civilian U.S. residents aged 18 years and older. National Health Interview Survey sampling weights with SUDAAN provided nationally representative population estimates.

RESULTS

An estimated 19 million people (10.1%) reported some mobility difficulty. The mean age of those with minor, moderate, or major difficulty ranged from 59 to 67 years. Of those reporting major difficulties, 32% said their problems began at aged 50 years or younger. Adjusted problem rates were higher among women (11.8%) than men (8.8%), and higher among African American (15.0%) than whites (10.0%). Persons with mobility difficulties were more likely to be poorly educated, living alone, impoverished, obese, and having problems conducting daily activities. Among persons with major mobility difficulties, 30.6% reported being frequently depressed or anxious, compared to 3.8% for persons without mobility difficulties.

CONCLUSIONS

Reports of mobility difficulties are common, including among middle-aged adults. Associations with poor performance of daily activities, depression, anxiety, and poverty highlight the need for comprehensive care for persons with mobility problems.

Methodological considerations for researchers and practitioners using pedometers to measure physical (ambulatory) activity

Researchers and practitioners require guidelines for using electronic pedometers to objectively quantify physical activity (specifically ambulatory activity) for research and surveillance as well as clinical and program applications. Methodological considerations include choice of metric and length of monitoring frame as well as different data recording and collection procedures. A systematic review of 32 empirical studies suggests we can expect 12,000-16,000 steps/day for 8-10-year-old children (lower for girls than boys); 7,000-13,000 steps/day for relatively healthy, younger adults (lower for women than men); 6,000-8,500 steps/day for healthy older adults; and 3,500-5,500 steps/day for individuals living with disabilities and chronic illnesses. These preliminary recommendations should be modified and refined, as evidence and experience using pedometers accumulates.

Measuring adherence to a self-care fitness walking routine

The purpose of this study is to develop and evaluate a theoretically appropriate measure for adherence to a self-care fitness walking routine. Self-care activities are very different from prescribed therapeutic regimens. One important difference is the determination of the activity prescription or behavioral standard. When the activity is classified as self-care, the behavioral standard is determined by the individual. When the activity is a prescribed therapeutic regimen, it is determined by the health care provider. Adherence to health related activities is usually calculated by comparing actual behaviors with an expert determined standard. When this technique is used to measure adherence to a self-care regimen, the theoretical assumption that self-care activities are self-prescribed has been ignored. In this study, adherence to the self-care activity fitness walking is calculated by comparing actual recorded fitness walking behaviors with the walker's own fitness walking intention.

Can young severely disabled stroke patients regain the ability to walk independently more than three months post stroke?

OBJECTIVE

To investigate the acquisition of ability to walk independently in young severely disabled stroke patients unable to walk three months after onset.

SETTING

A regional rehabilitation unit providing post-acute neurorehabilitation mainly for patients aged 16-65 years.

SUBJECTS AND METHODS

A retrospective analysis of records was undertaken for 152 stroke patients admitted consecutively over a three-year period. All had a combination of physical, cognitive and language impairments; male/female 98/54; median age 54 (IQR 47-60) years.

MAIN OUTCOME MEASURES

Time taken from stroke onset to regain the ability to walk safely and independently at least 5 metres around the hospital bay.

RESULTS

Seventy-five (49%) regained the ability to walk independently between 3 and 11 months post onset. Patients with cognitive impairments and neglect took longer to walk. Time from stroke onset to admission was longer in patients who did not walk (median 16.3 weeks), than in those who regained walking (median 12.7 weeks; p = 0.009). Independent positive associations were found between the time taken to walk and time from onset to referral for rehabilitation (p = 0.55; p < 0.001), and time from acceptance to admission (p = 0.30; p = 0.008).

CONCLUSION

With intensive specialist input, significant numbers of severely disabled young stroke patients can regain independent walking many months after onset, though late walkers may follow a slower recovery course. These results argue for investment in appropriate rehabilitation for these patients. Waiting list delays may prolong rehabilitation and potentially compromise cost effectiveness.

Optimization characteristics of walking with and without a load on the trunk of the body

Previous work showed that subjects naturally adopt a walking speed which optimizes energy cost of locomotion and stability of stride; however, no studies have examined whether these criteria are affected by carrying an external load. The purpose of this study was to compare optimization characteristics during loaded or unloaded walking. Energy cost and stride characteristics were measured for 10 subjects with and without a load on the trunk of the body of 10% of the body weight during 4 sessions. The first 2 sessions represent free walking at 2.5, 3, 3.5, 4, 4.5, and 5 km x hr.(-1). The last sessions represent free vs forced walking at constant speed (preferred frequency and +/- 10 PF and +/-20% of preferred frequency). Results show an effect of load on energy cost of walking but no effect on the optimal speed for stability. Furthermore, when carrying a load the subject does not adopt systematically the speed that minimizes physiological cost. Our findings suggest the necessity to consider this effect to prevent gait disturbance and maintain the health benefits of walking.

Compliance with physical activity recommendations by walking for exercise--Michigan, 1996 and 1998

Physical inactivity is an important modifiable risk factor for many diseases, including cardiovascular disease, cancer, diabetes, and osteoporosis. The 1996 Surgeon General's report (1) recommended that persons of all ages obtain "a minimum of 30 minutes of physical activity of moderate intensity (e.g., brisk walking) on most, if not all, days of the week." Walking is encouraged as one of the most accessible ways to be physically active (2), is the most commonly reported leisure-time physical activity (LTPA) in the United States, and is relatively common among groups that are typically inactive (e.g., the elderly and low-income groups) (3). To determine whether exercise characteristics (i.e., duration, frequency, and speed of walking) of Michigan adults met the Surgeon General's recommendations, the Michigan Department of Community Health analyzed data from the 1996 and 1998 Michigan Behavioral Risk Factor Surveillance System (BRFSS) for those who reported walking as their only LTPA. This report summarizes the results of this analysis, which indicate that most walkers need to increase the frequency and perhaps the speed of their walking to comply with recommendations.

Measuring development of a child's early walking: implications for clinical assessment of gait

This study examined the three-dimensional kinematics and motor development patterns in early walking gait longitudinally over 8 mo. and presents an example of walking development of one normal child which might be used for comparative purposes in the clinical assessment of gait.

Validity and reliability of the 6-minute walk test in a cardiac rehabilitation population

PURPOSE

Although the 6-minute walk test is commonly used to assess the functional status of patients with severe cardiopulmonary disease, few studies have tested its value in a cardiac rehabilitation (CR) population with milder disease status. The purpose of this study was to examine the validity and reliability of the 6-minute walk in a Phase II/III CR program.

METHODS

Ninety-four patients (61 men, 33 women) aged 63 +/- 10 years completed three 6-minute walks on nonconsecutive days. Patients also completed the Duke Activity Status Index (DASI) and the Short Form 36 Health Survey (SF-36). In addition, maximum metabolic equivalents (METs) from a symptom-limited graded exercise test were obtained from files.

RESULTS

The 6-minute walk was linearly related to maximum METs (r = 0.687, P < 0.001), supporting the validity of the test. Patients walked significantly farther in each 6-minute walk (F = 19.83, P < 0.001), and strong test-retest reliability was demonstrated (intraclass correlation = 0.97). Distance walked decreased with older age (F = 19.49, P < 0.001), with men walking farther than women (F = 7.19, P < 0.01). The 6-minute walk was moderately correlated with scores from the DASI (r = 0.502, P < 0.001), and the Physical Function subscale of the SF-36 (r = 0.624, P < 0.001).

CONCLUSIONS

The 6-minute walk is a valid and reliable method of assessing functional ability in a Phase II/III CR population. A learning effect of 6% was observed over the three walks; however, it is unknown if this learning effect will be retained over time. This test may be particularly valuable to smaller CR centers that want to document functional improvements but do not have access to conventional treadmill tests.

[The walking-counting test. A simple test for assessing the risk of falling]

BACKGROUND AND OBJECTIVE

Falls and fractures caused by falls are common in the elderly. Interventions to prevent such falls and/or fractures are available. But there are no appropriate tests in general practice for the targeted use of preventative measures. This prospective study was undertaken to validate a simple "walking and counting" test for assessing the risk of falling.

PATIENTS AND METHODS

92 patients of a general practice, aged between 70 and 96 years (64 women, 28 men) were included in the study. All patients were given the "walking and counting" test in which they would walk as quickly as possible along a stretch of 4 m, repeated immediately in a 3-step sequence while counting backwards from 100. The walking speed without counting was measured initially (vo), as was the speed during distraction by counting (vD). The difference between the two values, delta v%, measured the percentage change under distraction. In 80 patients it was possible to record the number of falls over the entire subsequent period of 12 months. All data were assessed by relative operating characteristics (ROC) and Bayesian analysis.

RESULTS

40 patients had falls in the follow-up period of 12 months, falls being more frequent the higher the age and if there had been previous falls. While all patients were able to do the test, individual values differed considerably. There was a statistical correlation between the calculated change in walking speed and the risk of falling. Using a threshold value of 20% slowing of the walking speed, the test sensitivity was 95% (0.51-0.81: 95% confidence interval) and the specificity 0.85 (0.71-0.93), with a positive predictive value of 0.77 (0.59-0.84).

CONCLUSION

The walking and counting test is a simple and informative test, more reliable than other parameters, to predict for an individual patient with danger of falling over a 12-months period. It provides the general practitioner with a tool for demanding appropriately targeted preventative measures.

Improvement of walking speed prediction by accelerometry and altimetry, validated by satellite positioning

Activity monitors based on accelerometry are used to predict the speed and energy cost of walking at 0% slope, but not at other inclinations. Parallel measurements of body accelerations and altitude variation were studied to determine whether walking speed prediction could be improved. Fourteen subjects walked twice along a 1.3 km circuit with substantial slope variations (-17% to +17%). The parameters recorded were body acceleration using a uni-axial accelerometer, altitude variation using differential barometry, and walking speed using satellite positioning (DGPS). Linear regressions were calculated between acceleration and walking speed, and between acceleration/altitude and walking speed. These predictive models, calculated using the data from the first circuit run, were used to predict speed during the second circuit. Finally the predicted velocity was compared with the measured one. The result was that acceleration alone failed to predict speed (mean r = 0.4). Adding altitude variation improved the prediction (mean r = 0.7). With regard to the altitude/acceleration-speed relationship, substantial inter-individual variation was found. It is concluded that accelerometry, combined with altitude measurement, can assess position variations of humans provided inter-individual variation is taken into account. It is also confirmed that DGPS can be used for outdoor walking speed measurements, opening up new perspectives in the field of biomechanics.

Gender differences in hallway ambulation by older adults hospitalized for medical illness

Bed rest during hospitalization predisposes patients to declines in balance, strength, and bone mass, and may contribute to falls and fractures after discharge. Periodic ambulation may help prevent these adverse consequences. However it is unknown to what extent men and women ambulate during hospitalization. We observed hallway ambulation by adults age 55 and over hospitalized on 3 medical units of the University of Wisconsin Hospital. Hallways were observed during 24 three-hour periods covering the interval from 8 AM to 8 PM. Prior to each 3-hour observation, nursing staff were asked about characteristics of older patients who were able to ambulate in the hallways. Results showed that women spent significantly less time ambulating compared to men (1.6 versus 4.2 minutes per 3-hour period, p = .047), and were less likely to walk independent of hospital staff (10.4% versus 23.5%, p = .049). If these findings of gender differences in mobility are validated in other studies, they imply that in-hospital rehabilitation programs may need to particularly target women.

Walking compared with vigorous physical activity and risk of type 2 diabetes in women: a prospective study

CONTEXT

Although many studies suggest that physical activity may reduce risk of type 2 diabetes, the role of moderate-intensity activity such as walking is not well understood.

OBJECTIVES

To examine the relationship of total physical activity and incidence of type 2 diabetes in women and to compare the benefits of walking vs vigorous activity as predictors of subsequent risk of type 2 diabetes.

DESIGN AND SETTING

The Nurses' Health Study, a prospective cohort study that included detailed data for physical activity from women surveyed in 11 US states in 1986, with updates in 1988 and 1992.

PARTICIPANTS

A total of 70,102 female nurses aged 40 to 65 years who did not have diabetes, cardiovascular disease, or cancer at baseline (1986).

MAIN OUTCOME MEASURE

Risk of type 2 diabetes by quintile of metabolic equivalent task (MET) score, based on time spent per week on each of 8 common physical activities, including walking.

RESULTS

During 8 years of follow-up (534, 928 person-years), we documented 1419 incident cases of type 2 diabetes. After adjusting for age, smoking, alcohol use, history of hypertension, history of high cholesterol level, and other covariates, the relative risks (RRs) of developing type 2 diabetes across quintiles of physical activity (least to most) were 1.0, 0.77, 0.75, 0.62, and 0.54 (P for trend <.001); after adjusting for body mass index (BMI), RRs were 1.0, 0.84, 0.87, 0.77, and 0.74 (P for trend = .002). Among women who did not perform vigorous activity, multivariate RRs of type 2 diabetes across quintiles of MET score for walking were 1.0, 0.91,0.73, 0.69, and 0.58 (P for trend <.001). After adjusting for BMI, the trend remained statistically significant (RRs were 1.0, 0.95, 0.80, 0.81, 0.74; P for trend = .01). Faster usual walking pace was independently associated with decreased risk. Equivalent energy expenditures from walking and vigorous activity resulted in comparable magnitudes of risk reduction.

CONCLUSIONS

Our data suggest that greater physical activity level is associated with substantial reduction in risk of type 2 diabetes, including physical activity of moderate intensity and duration.

The use of alcohol and other psychoactive substances by victims of traffic accidents in Greece

Alcohol is one of the main causes of traffic accidents worldwide. Its use decreases significantly the driving ability of an individual as well as the reflexes of a pedestrian increasing in this way the possibilities of their involvement in motor-vehicle accidents. The above possibilities are increased when a psychoactive substance has been taken in combination with alcohol due to their synergistic effect. The Laboratory of Forensic Medicine and Toxicology of the University of Athens is authorized to perform the toxicological investigation of traffic accidents that happen in the major part of Greece. The findings of the toxicological analyses that were performed in our laboratory during the years 1995 to 1997 are classified according to the alcohol concentration and the kind of psychoactive substance detected as well as to the gender and the age of the victims, drivers or pedestrians. The results of the above classification are evaluated and the conclusions regarding alcohol, drugs and traffic accidents in Greece are discussed thoroughly.

Who walks? Factors associated with walking behavior in disabled older women with and without self-reported walking difficulty

OBJECTIVES

To determine how severity of walking difficulty and sociodemographic, psychosocial, and health-related factors influence walking behavior in disabled older women.

DESIGN

Cross-sectional analyses of baseline data from the Women's Health and Aging Study (WHAS).

SETTING

An urban community encompassing 12 contiguous zip code areas in the eastern portion of Baltimore City and part of Baltimore County, Maryland.

PARTICIPANTS

A total of 920 moderately to severely disabled community-resident women, aged 65 years and older, identified from an age-stratified random sample of Medicare beneficiaries.

MEASUREMENTS

Walking behavior was defined as minutes walked for exercise and total blocks walked per week. Independent variables included self-reported walking difficulty, sociodemographic factors, psychological status (depression, mastery, anxiety, and cognition), and health-related factors (falls and fear of falling, fatigue, vision and balance problems, weight, smoking, and cane use).

RESULTS

Walking at least 8 blocks per week was strongly negatively related to severity of walking difficulty. Independent of difficulty level, older age, black race, fatigue, obesity, and cane use were also negatively associated with walking; living alone and high mastery had a positive association with walking.

CONCLUSIONS

Even among functionally limited women, sociocultural, psychological, and health-related factors were independently associated with walking behavior. Thus, programs aimed at improving walking ability need to address these factors in addition to walking difficulties to maximize participation and compliance.

[Nature and severity of injuries in traffic accident victims]

The objective of this retrospective study is to characterize the nature and severity of injuries of hospitalized traffic accident victims using the "Abbreviated Injury Scale" (AIS). Two-hundred and twenty such patients in a trauma reference hospital in Sao Paulo, Brazil were assessed. One-hundred and eleven of them were pedestrians, eighty-three vehicular passengers and twenty-six motorcyclists. The most common injuries were of the limbs, pelvic girdle and head/neck. Injury severity in all these patients was AIS = 3. Two-thirds of the forty-five victims who died were pedestrians.

Children's exposure to traffic and pedestrian injuries

OBJECTIVES

The purpose of this study was to estimate children's exposure to traffic (number of streets crossed) and to determine the role of exposure in pedestrian injury.

METHODS

Questionnaires were distributed to a random sample of 4080 first- and fourth-grade children in 43 Montreal schools.

RESULTS

When analyzed by police district, injury and exposure rates were positively correlated (r2 = 0.53). Crossings were similar by sex but increased with age and were inversely related to socioeconomic status.

CONCLUSIONS

These results suggest that although children's exposure to traffic could be reduced by transporting them to school, a more reasonable prevention strategy involves environmental changes.

Wandering: a significant problem among community-residing individuals with Alzheimer's disease

This study evaluated the frequency, predictors, and effects of wandering in a population-based sample of 193 individuals with Alzheimer's disease (AD). Although wandering occurred in subjects at all levels of cognitive impairment, analysis of variance indicated that for the group as a whole, greater frequency of wandering was associated with significantly more impairment in cognition, day-to-day functioning, and behavior. Caregiver distress also increased significantly with increased frequency of wandering. Logistic regression modeling identified functional impairment and disruptive behavior problems as the strongest independent predictors of wandering occurring within the past week. Cluster analysis revealed four characteristic groups of wanderers that represented a continuum of wandering frequency, each having a unique pattern of other behavioral disturbances. Based on this analysis, we recommend further evaluation and the development of possible treatment strategies that address the individual differences found among AD patients who wander.

How readily will sheep walk for a preferred forage?

We studied how ewes chose between a poor-quality hay freely available and a good-quality one offered in limited quantities when they walked across an indoor test area. To determine what dictates a ewe's behavior, we varied the accessibility of the good hay by changing the quantity that rewarded the walk (2, 4, 8, 16, or 32 g) and the distance walked (23 or 46 m). Ewes were more reluctant to walk for the good hay as reward level decreased. For a given reward, average preference for good hay (P(GH)) also fell when ewes had to walk 46 m to be rewarded. In each comparison, for the same reward to distance (Rew/Dist) ratio, average P(GH) did not differ. We determined the correlation between P(GH) and Rew/Dist using data from three experiments with ewes offered a similar choice. The best model accounted for 85% of the corrected total sum of squares. Good hay procurement cost thus dictated a ewe's behavior. Choice was suboptimal only, either due to the test conditions, discrimination errors, or an animal's will to select a mixed diet. Our results suggest that, within its perceptive field, a ewe will equally walk to resources that have the same edible biomass relative to the distance to the patch.