Physical Activity, Body Composition, and Perceived Quality of Life of ...

Physical Activity, Body Composition, and Perceived Quality of Life of Adults with Visual Impairments Elizabeth A. Holbrook, Jennifer L. Caputo, Tara L. Perry, Dana K. Fuller, and Don W. Morgan Abstract: Relatively little is known about the health and fitness of adults with visual impairments. This article documents the physical activity levels and body-composition profiles of young and middle-aged adults with visual impairments and addresses the concomitant effects of these factors on perceived quality of life.

High levels of physical inactivity have contributed to the growing epidemic of obesity in the United States (Daniels, 2006; Pi-Sunyer, 2002). Given the negative health consequences that are associated with leading a sedentary lifestyle, it is discouraging to note that 53% of women and 49% of men do not engage in regular physical activity (Haskell et al., 2007). Persons with disabilities are also less physically active than are those without disabilities and are increasingly prone to further health complications (U.S. Department of Health and Human Services, USDHHS, 2000). Among the 54 million of Americans with disabilities, more than half do not engage in any leisure-time physical activity (USDHHS, 2000). Despite the pervasiveness of inactivity among persons with disabilities, few guidelines exist to support the efficacy of physical activity for individuals with visual impairments (that is, those who are blind or have low vision) (Harrison, 2006). ©2009 AFB, All Rights Reserved

Previous research Past research that has quantified the physical activity levels of persons with visual impairments has been limited to children and older adults. These studies have reported lower levels of physical activity and a greater occurrence of obesity among individuals who are visually impaired compared to the general U.S. population (Campbell, Crews, Moriarty, Zack, & Blackman, 1999; Crews & Campbell, 2001). Among children with visual impairments, studies have described lower levels of cardiovascular fitness, unhealthy body-composition profiles, and diminished levels of physical activity compared to age- and gendermatched sighted children (Blessing, McCrimmon, Stovall, & Williford, 1993; Hopkins, Gaeta, Thomas, & Hill, 1987; Lieberman & McHugh, 2001; Seelye, 1983). At the other end of the age spectrum, a greater occurrence of comorbid conditions, depression, and limitations on Journal of Visual Impairment & Blindness, January 2009

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activity has been noted in older adults with visual impairments (Campbell et al., 1999; Crews & Campbell, 2001). The generalizability of research examining the roles of physical activity on the health of individuals with visual impairments has been hampered by a number of methodological constraints. The lack of consistency in determining various components of physical fitness, physical activity levels, and visual status among participants has led to difficulty in comparing findings across studies. In addition, past investigations have featured small samples that have been comprised primarily of school-aged children and older adults and have often neglected to report procedures that were used to recruit the participants. To evaluate the discrepancy in physical activity levels of persons with and without visual impairments more fully, it is necessary to include persons aged 18 to 60 years, who comprise nearly 70% of the population of persons with visual impairments (Leonard, 2002). Moreover, a direct appraisal of physical activity, rather than questionnaire-based assessments that were featured in earlier reports, would help clarify the relationship between physical activity and health among individuals who are visually impaired. Classifying individuals as having low vision or being blind has also complicated attempts to relate patterns of physical activity to the severity of visual impairment. By defining visual impairment as a function of visual acuity or visual field, researchers can more fully understand the impact of the severity of visual impairment on physical activity and health. Finally, although quality of life is an accepted component of general well-being, the association between physical activity and perceived quality of life in

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Journal of Visual Impairment & Blindness, January 2009

individuals with visual impairments has not been examined. Against this backdrop, the purpose of our study was to quantify levels of habitual physical activity, body composition, and perceived quality of life in young and middle-aged men and women with various degrees of visual impairment. A secondary purpose was to determine whether the participants’ perceived quality of life could be predicted from the interactive effect of physical activity and the severity of visual impairment.

Methods PARTICIPANTS Participation in the study was limited to men and women with a best-corrected visual acuity ranging from 20/200 to no light perception. Twenty-five adults aged 18 to 60 with no known mobility limitations consented to participate. The sample, which included 15 men and 10 women, was stratified into three groups according to the International Classification of Diseases (ICD) schematic for defining visual impairment (World Health Organization, 2006). On the basis of these classifications, 8 participants met the criteria for mild visual impairment (ICD Classification 1), 9 were classified as having a moderate visual impairment (ICD Classifications 2– 4), and 8 met the criteria for severe visual impairment (ICD Classification 5). The sample included 13 participants with congenital visual impairments and 12 with adventitious visual impairments. Although 6 participants reported having controlled diabetes, none displayed any apparent physical limitations in mobility. Of the 20 participants who required a mobility aid because of ©2009 AFB, All Rights Reserved

their visual impairments, 16 reported using a long cane and 4 walked with a dog guide. During the study, 21 participants were employed and 4 were full-time college students.

PROCEDURES Approval for the study was obtained from the Institutional Review Board at Middle Tennessee State University. Participants were initially solicited through various statewide support organizations for persons with visual impairments, and recruitment continued via word of mouth throughout the local community. Because of transportation difficulties, participants had the option of undergoing testing at the university or in their homes. Session 1 After written informed consent was obtained, the participants were interviewed to determine their visual acuity and mobility status, employment background, and whether or not they used a mobility aid (a long cane, dog guide, or sighted guide). Perceived quality of life was assessed using the Low Vision Quality of Life Questionnaire (LVQOL). The LVQOL (alpha ⫽ .88; r ⫽ .72), a 25-item survey that is intended for use with individuals with a variety of cause-related visual impairments, addresses aspects of daily living that are associated with mobility, reading, and lifestyle adjustments that are related to impaired vision (Wolffsohn & Cochrane, 2000). The LVQOL was read to all the participants, regardless of their visual status. Measurements of height, weight, and skinfold thickness were obtained to characterize selected physical features of the sample. The participants were weighed ©2009 AFB, All Rights Reserved

barefoot on a digital SECA scale (Germany; Model 770). Weight was measured to the nearest tenth of a pound and converted to kilograms. Height measurements were taken to the nearest eighth of an inch using a wall-mounted stadiometer (SECA, Germany; Model 222) and converted to meters. Body mass index (BMI) was calculated by dividing body mass (kilograms) by height squared (m2). For in-home evaluations, a validated, portable stadiometer (SECA, Germany; Model 214) was used to measure height. Skinfold thickness was evaluated using a Harpendon skinfold caliper (Creative Health Products, Ann Arbor, Michigan) at three standard sites (men: chest, triceps, and subscapular, women: triceps, suprailiac, and thigh) according to guidelines prescribed by the American College of Sports Medicine (ACSM; 2006). Skinfold values were used to calculate body density according to appropriate generalized prediction equations developed by Jackson and Pollock (1985). Populationspecific formulas were subsequently used to derive the percentage of body fat from body density values (Nieman, 2007). Daily physical activity levels were quantified with a Step Activity Monitor (SAM; Cyma, Seattle, WA; Model SW3). Using velcro straps, the SAM was attached to the right leg, just above the lateral malleolus (ankle bone). Each participant completed a number of walking trials to ensure that the monitor counted steps accurately. Walking trials were conducted with the use of the participant’s mobility aid, such as a long cane or dog guide, to replicate walking in a nonlaboratory setting. The participants then demonstrated the correct placement and removal of the activity monitor. The SAM Journal of Visual Impairment & Blindness, January 2009

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was worn over the course of a seven-day period, and data from four randomly selected days (three weekdays and one weekend day) were analyzed to estimate daily physical activity. Overall daily step counts and patterns of daily physical activity were recorded, including steps per unit of time (steps per minute), the percentage of inactive time, and the percentage of active time spent at low (1–30 steps per minute), moderate (31– 80 steps per minute), and high (more than 80 steps per minute) levels of physical activity (Boone & Coleman, 2006). Because the SAM reports step counts only for the leg on which it is worn, average daily step counts and intensity counts were doubled to reflect steps taken with both legs. Session 2 A second meeting was required to gather SAM-recorded data on physical activity, as well as to debrief the participants. Additional unprompted insights were provided by nearly all the participants during the debriefing session, including perceived barriers to physical activity and general opinions regarding the health status of the greater community of adults with visual impairments.

DATA ANALYSIS To examine the interaction of the severity of visual impairment and gender on the percentage of body fat; perceived quality of life; daily step counts; the percentage of the total time spent inactive; and the percentage of time spent at low, moderate, and high levels of physical activity, seven 3 (mild, moderate, severe) x 2 (male, female) factorial analyses of variance (ANOVAs) were performed. If an overall statistical difference was observed

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for a given variable, the Tukey HSD test was used to identify the location of pairwise differences. Hierarchical multiple regression was used to test for an interactive effect between the severity of visual impairment and the average daily step count on perceived quality of life. For all comparisons, a significance level of p ⬍ .05 was used.

Results The results of the body-composition analysis, which featured measurements of height, weight, percentage of body fat, and BMI, are displayed in Table 1. No interaction was found between the severity of visual impairment and gender on percentage of body fat, F(2, 19) ⫽ 1.18, p ⫽ .33, and no main effect was found for the severity of visual impairment, F(2, 19) ⫽ 1.29, p ⫽ .30. However, a main effect for gender was observed, F(1,19) ⫽ 24.2, p ⫽ .00, indicating that across levels of visual impairment, the percentage of body fat was significantly higher for women (37%) than for men (26%). The data on physical activity are presented in Table 2. A factorial ANOVA revealed no interaction between the severity of visual impairment and gender for four of the physical activity variables: average daily step counts, F(2, 19) ⫽ 1.10, p ⫽ .35; percentage of time at low activity, F(2, 19) ⫽ 1.09, p ⫽ .36; percentage of time at moderate activity, F(2, 19) ⫽ 0.08, p ⫽ .93; and percentage of time inactive, F(2, 19) ⫽ 1.81, p ⫽ .19. Although statistically nonsignificant, a trend was noted for the interaction between the severity of visual impairment and gender on the percentage of active time spent at high levels of physical activity, F(2, 19) ⫽ 2.86, p ⫽ .08, such that the women who were mildly visually ©2009 AFB, All Rights Reserved

Table 1 Demographic characteristics, body composition, and perceived quality of life of the participants (N ⴝ 25). Age (M ⫾ SD)

Height (inches) (M ⫾ SD)

Mass (kilograms) (M ⫾ SD)

Mild (N ⫽ 8) Male (n ⫽ 4) Female (n ⫽ 4)

35.9 ⫾ 15.0 35.3 ⫾ 12.3 36.5 ⫾ 19.2

67.6 ⫾ 2.9 69.2 ⫾ 2.0 66.0 ⫾ 3.0

Moderate (N ⫽ 9) Male (n ⫽ 6) Female (n ⫽ 3)

39.4 ⫾ 10.9 41.0 ⫾ 12.7 36.3 ⫾ 7.4

66.9 ⫾ 5.0 69.8 ⫾ 2.3 61.1 ⫾ 3.6

Severe (N ⫽ 8) Male (n ⫽ 5) Female (n ⫽ 3)

42.8 ⫾ 10.4 40.2 ⫾ 11.9 47.0 ⫾ 7.21

Level of visual impairment

Total (N ⫽ 25) 39.4 ⫾ 12.0 Male (n ⫽ 15) 39.2 ⫾ 11.7 Female (n ⫽ 10) 39.6 ⫾ 12.0

BMI (kg/m2) (M ⫾ SD)

LVQOL (M ⫾ SD)

84.1 ⫾ 19.1 29.1 ⫾ 5.9 93.7 ⫾ 21.4 25.2 ⫾ 4.5 74.4 ⫾ 12.3 33.1 ⫾ 4.5

28.5 ⫾ 6.3 30.4 ⫾ 7.1 26.7 ⫾ 5.6

91.63 ⫾ 16.93 99.75 ⫾ 18.87 83.50 ⫾ 11.70

88.2 ⫾ 16.3 31.6 ⫾ 6.2 96.1 ⫾ 13.8 28.0 ⫾ 3.7 72.4 ⫾ 4.6 38.9 ⫾ 1.9

30.5 ⫾ 4.1 30.7 ⫾ 4.9 30.1 ⫾ 2.3

88.89 ⫾ 17.60 94.50 ⫾ 16.33 71.67 ⫾ 7.09

66.8 ⫾ 3.8 87.7 ⫾ 18.4 30.8 ⫾ 11.9 67.3 ⫾ 4.1 79.8 ⫾ 19.6 24.5 ⫾ 10.5 66.1 ⫾ 4.0 100.8 ⫾ 2.0 41.4 ⫾ 1.8

30.6 ⫾ 6.9 27.3 ⫾ 5.9 36.1 ⫾ 4.8

92.50 ⫾ 23.55 99.20 ⫾ 20.30 81.33 ⫾ 28.60

67.1 ⫾ 3.9 68.7 ⫾ 3.0 64.6 ⫾ 3.9

29.9 ⫾ 5.6 29.5 ⫾ 5.7 30.5 ⫾ 5.8

90.20 ⫾ 18.85 97.47 ⫾ 17.20 79.30 ⫾ 16.34

% body fat (M ⫾ SD)

86.7 ⫾ 17.3 30.6 ⫾ 8.1 90.0 ⫾ 18.3 26.1 ⫾ 6.6 81.7 ⫾ 15.1 37.3 ⫾ 4.8

Note: BMI ⫽ body mass index; higher scores on the Low Vision Quality of Life questionnaire (LVQOL) denote a higher perceived quality of life (scores based on a possible total score of 125 points).

impaired displayed a bias toward a greater percentage of active time spent at high intensities of activity (14.1%) than did the men (5.6%). Conversely, the women who were severely visually impaired tended to

exhibit a similar percentage of highintensity active time (4.7%) compared to the men (7.0%). Nearly identical values for the percentage of active time spent at high levels of activity were also observed for

Table 2 Physical activity levels of the participants (N ⴝ 25). Level of visual impairment

Steps (M ⫾ SD)

Low (M ⫾ SD)

Moderate (M ⫾ SD)

High (M ⫾ SD)

Inactive (M ⫾ SD)

Mild (N ⫽ 8) Male (n ⫽ 4) Female (n ⫽ 4)

8962 ⫾ 3994 9464 ⫾ 4677 8460 ⫾ 3830

65.61 ⫾ 8.35 68.45 ⫾ 8.81 62.78 ⫾ 7.97

24.68 ⫾ 6.44 26.05 ⫾ 7.97 23.3 ⫾ 5.31

9.80 ⫾ 7.16 5.55 ⫾ 3.22 14.05 ⫾ 7.82

78.63 ⫾ 7.73 74.88 ⫾ 8.91 82.38 ⫾ 4.74

Moderate (N ⫽ 9) Male (n ⫽ 6) Female (n ⫽ 3)

7307 ⫾ 3677 6255 ⫾ 2816 9413 ⫾ 4928

71.51 ⫾ 8.22 71.15 ⫾ 8.36 72.23 ⫾ 9.73

24.63 ⫾ 8.24 25.10 ⫾ 9.86 23.70 ⫾ 5.20

4.09 ⫾ 3.42 4.02 ⫾ 2.76 4.23 ⫾ 5.26

78.11 ⫾ 10.15 80.50 ⫾ 8.36 73.33 ⫾ 13.64

Severe (N ⫽ 8) Male (n ⫽ 5) Female (n ⫽ 3)

7906 ⫾ 1652 8400 ⫾ 1733 7081 ⫾ 1381

68.32 ⫾ 7.59 65.84 ⫾ 8.23 72.47 ⫾ 5.02

25.69 ⫾ 4.68 27.26 ⫾ 5.14 23.07 ⫾ 7.57

6.15 ⫾ 4.18 7.04 ⫾ 4.93 4.67 ⫾ 2.72

79.00 ⫾ 3.79 78.80 ⫾ 4.91 79.33 ⫾ 1.31

Total (N ⫽ 25) Male (n ⫽ 15) Female (n ⫽ 10)

8028 ⫾ 3232 7826 ⫾ 3212 8332 ⫾ 3410

68.60 ⫾ 8.12 68.66 ⫾ 8.15 68.52 ⫾ 8.50

24.98 ⫾ 6.44 26.07 ⫾ 7.54 23.35 ⫾ 4.14

6.58 ⫾ 5.46 5.43 ⫾ 3.70 8.29 ⫾ 7.26

78.56 ⫾ 7.49 78.43 ⫾ 7.37 78.75 ⫾ 8.06

Note: Steps ⫽ average daily step counts derived from four randomly selected days (counting both legs); low ⫽ percentage of active time spent at a low-intensity activity (1 to 30 steps per minute), moderate ⫽ percentage of active time spent at a moderate-intensity activity (31 to 80 steps per minute), high ⫽ percentage of active time spent at a high-intensity activity (more than 80 steps per minute); and inactive ⫽ percentage of average time spent inactive.

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women and men with moderate visual impairments (4.2% and 4.0%, respectively). With respect to perceived quality of life, there was no interaction between the severity of visual impairment and gender on perceived quality of life, F (2, 19) ⫽ 0.07, p ⫽ .93. A main effect for gender on perceived quality of life was detected, F(1, 19) ⫽ 6.49, p ⫽ .02, indicating that when viewed across levels of visual impairment, the men demonstrated a higher LVQOL score (97.5) than did the women (79.3). The main effect for the severity of visual impairment on quality of life was not statistically significant, F(2,19) ⫽ 0.51, p ⫽ .61. Hierarchical regression demonstrated that the interaction of the severity of visual impairment and the average daily step count did not significantly predict perceived quality of life in our sample, F(2, 19) ⫽ 1.29, p ⫽ .30, R2 delta ⫽ .12. In addition, there were no main effects for the severity of visual impairment and the average daily step count on perceived quality of life, F(5, 19) ⫽ 0.60, p ⫽ .70, Adj. R2 ⫽ .00.

Discussion Physical activity is acknowledged to be an essential component of a healthy lifestyle. The benefits of physical activity continue to emerge and are known to encompass many facets of physical and mental well-being. Nevertheless, despite current health recommendations, the majority of the U.S. population does not participate in regular physical activity (USDHHS, 2000). Furthermore, the prevalence of inactivity is considerably greater among individuals with disabilities (Rimmer, Riley, Wang, Rauworth, & Jurkowski, 2004; USDHHS, 2000). Lim-

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ited research on persons with visual impairments has suggested that the sedentary lifestyles of children with visual impairments may predispose these children to numerous obesity-related health conditions during adulthood (CapellaMcDonnall, 2007). Hence, the focus of our investigation was to quantify levels of habitual physical activity, body composition, and perceived quality of life in young and middle-aged men and women with various levels of visual impairments. A secondary purpose was to determine the interactive effect of physical activity and severity of visual impairment on the participants’ perceived quality of life. To our knowledge, this is the first investigation to document the separate and combined roles of gender and severity of visual impairment on physical activity, body composition, and perceived quality of life in adults with visual impairments.

PHYSICAL ACTIVITY The average daily step counts taken by the participants ranged from 3,208 steps to 15,530 steps, with a group mean of 8,028 steps per day. This average volume of physical activity falls below the physical activity recommendation of 10,000 steps per day, a level endorsed by USDHHS and the Centers for Disease Control and Prevention (CDC), which equates with approximately 30 minutes of daily physical activity (Tudor-Locke & Bassett, 2004). In addition, the mean daily physical activity level of the participants was considerably lower than the activity level of similarly aged healthy adults (11,075 steps per day) measured using the same physical activity monitor (SAM) that was used in our study (Cavanaugh, ©2009 AFB, All Rights Reserved

Coleman, Gaines, Laing, & Morey, 2007). Furthermore, the mean physical activity levels of the participants (8,028 steps per day and 298.5 minutes of daily activity) were nearly identical to values reported among older adults with functional limitations (aged 79.3 years ⫾ 4.5 years. 7,682 steps per day, 298.0 minutes of daily activity) (Cavanaugh et al., 2007). Taken together, these findings suggest that when similar methods of quantifying physical activity are used, adults with visual impairments are less physically active than is the general U.S. adult population and are not achieving health-producing levels of physical activity. In addition to the quantity of physical activity performed daily, the quality of physical activity is also an important factor in producing health benefits. The recommendation by CDC and ACSM is to incorporate moderately to vigorously intense activities on most days of the week (Haskell et al., 2007; Pate et al., 1995). With respect to our study, the participants spent not only a relatively low percentage of the day being physically active (just over 20%), but spent an average of less than 7% of their total active time each day at moderate (5.4%) or high (1.4%) intensities of physical activity. On the basis of these findings, physical activities that the participants engaged in may not have been performed at the volume, duration, or intensity necessary to improve their overall health status or to reduce the incidence of chronic diseases. In general, the participants’ mean SAM scores did not vary by the severity of visual impairment or gender. These findings differ from those of previous studies that reported lower pedometer-deter©2009 AFB, All Rights Reserved

mined levels of physical activity in male and female young adults and children with visual impairments (Lieberman, Stuart, Hand, & Robinson, 2006; Suzuki et al., 1991), as well as sighted children and adults (Tudor-Locke & Myers, 2001). One potential explanation for the lack of a difference according to gender among our adult participants may be related to the predominant reliance on public transportation. This dependence on public transportation is likely to be more prevalent among persons with visual impairments than among the general U.S. population, especially when traveling in unfamiliar areas. Conversely, gender differences in the physical activity patterns of youths with visual impairments may be a function of pediatric studies being conducted at specialized schools for students with visual impairments, an environment in which students can ambulate safely throughout the campus. Although statistically nonsignificant, we observed a tendency among the women, but not among the men, with mild visual impairments to spend a greater percentage of time at high levels of physical activity. Although this observation should be regarded with caution in light of our small sample, it was interesting to note that the women with mild visual impairments were also less likely than the men with mild visual impairments to use a mobility aid. In follow-up conversations, these women indicated that the perceived stigma associated with the use of a mobility aid would cause them to avoid activities outside the home, thus hindering their ability to engage in a more active lifestyle. Not using a cane or other mobility aid indicated that the female participants felt Journal of Visual Impairment & Blindness, January 2009

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more confident in their ability to ambulate freely, thus increasing their likelihood of engaging in physical activity.

BODY COMPOSITION The assessment of skinfold thicknesses revealed mean fat percentages of 26% among the male participants and 37% among the female participants. These relative levels of adiposity greatly exceed the recommended range of healthy levels of body fat (10% to 22% for men and 20% to 32% for women) (Lohman, 1982). Ratios of weight to height were also calculated to facilitate comparisons with past investigations featuring BMI as the primary descriptor of body composition. Data from our study revealed an average BMI of 29.9 kg/m2 ⫾ 5.6 kg/m2, signifying an overweight classification in our sample of adults with visual impairments (ACSM, 2006). These results parallel the findings of Ray, Horvat, Williams, and Blasch (2007), who reported an average BMI of 30 kg/m2 among adults with visual impairments who were of the same mean age (M ⫽ 39 years) as our sample. While the average BMI of our sample of adults with visual impairments was somewhat higher than that reported for the general U.S. adult population (26 kg/m2), the incidences of obesity and extreme obesity appear to be greater in our sample. Compared to the general U.S. population, of whom 32.9% are obese (USDHHS, 2007), 44% of the participants exceeded the BMI criterion (greater than or equal to 30.0 kg/m2) for adult obesity. Moreover, 16% of participants who were classified as obese met the criteria for either moderate (35.0 kg/m2 to 39.9 kg/m2) or extreme (greater than or

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equal to 40.0 kg/m2) obesity (American College of Sports Medicine, 2006). Past investigations involving children and adults with visual impairments have reported direct associations between the degree of visual impairment and BMI or skinfold thickness (Hopkins et al., 1987; Ray et al., 2007). This relationship was not observed in our study, since the participants displayed similar percentages of body fat across levels of severity of visual impairment (mild ⫽ 29.1%, moderate ⫽ 31.6%, and severe ⫽ 30.8%). An examination of the data presented in Table 1 revealed that the values for the average percentage of body fat were generally in the unhealthy range for both the men and the women (Nieman, 2007). This finding suggests that independent of the severity of visual impairment, adults with visual impairments may exhibit a propensity toward a greater accumulation of weight and body fat. Viewed collectively, our sample of men and women with visual impairments had a body-composition profile that was characterized by high levels of relative weight and adiposity. Similar data were reported by Weil et al. (2002), who found that adults with visual impairments were 1.5 times more likely to be obese than were sighted adults. From a clinical perspective, this observation is consistent with the higher prevalence of comorbidity and premature mortality among adults with visual impairments.

PERCEIVED QUALITY OF LIFE The results of the quality-of-life assessment revealed no significant interaction between the severity of visual impairment and the average daily step count on perceived quality of life. In addition, neither ©2009 AFB, All Rights Reserved

visual impairment nor the average daily step count independently affected the participants’ ratings of their perceived quality of life. This latter finding was not anticipated, since previous studies of adults have reported greater emotional distress and reductions in functional status and perceived quality of life with the increased severity of visual impairment (Haymes, Johnston, & Heyes, 2002; Stelmack, 2001; Wang, Mitchell, & Smith, 2000). Moreover, physical activity has been shown to have a positive influence on the quality of life of younger and older healthy adults (Brown et al., 2003; Rejeski & Mihalko, 2001). We speculate that the average physical activity levels of the participants may not have been sufficient to elicit health-related improvements in the quality of their lives. As Brown et al. (2003) noted, persons who achieved the USDHHS- and ACSMrecommended levels of physical activity were more likely to report a higher level of health-related quality of life than were those who led a less active lifestyle. The lack of agreement between our data and previous findings may also be related to the use of indirect measures of physical activity in earlier studies (Brown et al., 2003; Brown et al., 2004; Vuillemin et al., 2005). Although we did not find an interaction between visual impairment and the average daily step count on perceived quality of life in our sample, we observed a significant main effect for gender on perceived quality of life, indicating that the quality of life of the women was consistently lower than that of the men. Although a lower perceived quality of life among women is a common observation in the general population (Zahran et al., 2005), our study was the first to report gender-specific findings derived ©2009 AFB, All Rights Reserved

from a vision-related quality-of-life questionnaire that was administered to adults with visual impairments. Previous authors have consistently referred to the difficulty in assessing the health-related quality of life of individuals who are visually impaired (de Boer et al., 2004; Margolis et al., 2002; Stelmack, 2001). Despite the fact that the manifestation, stability, and progression of diseases and comorbid conditions collectively influence the quality of life of a person with low vision or blindness, questionnaires have often failed to address these issues comprehensively (Margolis et al., 2002). Although the LVQOL is considered a valid and reliable instrument for assessing the quality of life of persons with low vision (de Boer et al., 2004, 2005; Wolffsohn & Cochrane, 2000), the results of the perceived quality-of-life assessment should be regarded with some caution. Among individuals who are blind, the inability to perform certain tasks because of vision-related challenges may not always be perceived as a problem. We found, for example, that higher quality-of-life scores were often reported by the participants with the most severe visual impairments than by the participants with low vision who could still perform selected tasks, albeit with extreme difficulty. In view of this potential limitation, multidimensional quality-of-life assessment tools that are appropriate for all levels of visual impairments, such as the Vision Core Module 1 or Impact of Vision Impairment questionnaires, should be considered viable methods for assessing the perceived quality of life of persons with low vision and blindness. Journal of Visual Impairment & Blindness, January 2009

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Conclusions and future research directions A primary conclusion of our study is that no statistically significant differences in physical activity, body composition, and perceived quality of life were observed between the male and female participants with different levels of visual impairment. However, the women had higher levels of relative adiposity and lower perceptions of quality of life than did the men. Our results also demonstrated that perceived quality of life among adults who are visually impaired cannot be predicted from physical activity level, severity of visual impairment, or the combined influence of these variables. Because of the inherent limitations associated with a small volunteer sample of participants, the generalizability of our findings is limited. It is possible that by recruiting a volunteer sample of participants, persons at the extreme levels of physical fitness (that is, highly fit or highly unfit) may have been less likely to participate, thus limiting the scope of our findings. Therefore, to document further the separate and interactive effects of the severity of visual impairment and gender on indices of physical and mental wellbeing, future research in this area should incorporate larger, randomized samples of participants. In addition, the establishment of a standardized classification system that clearly distinguishes among various levels of visual impairment is essential. In our study, we attempted to maximize the comprehensibility of levels of visual impairment by using an internationally recognized criterion for defining visual impairment. Finally, while perceived quality of life did not vary across

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levels of physical activity and severity of visual impairment, this aspect of health deserves further study in light of data that have supported a positive association between physical activity and quality of life. Given the suboptimal physical activity and body-composition profiles exhibited by the male and female participants, it is imperative to educate both advocates for and persons with visual impairments regarding the health-related needs of this population. By increasing accessibility to physical activity programs for children and adolescents with visual impairments, it may also be possible to establish sound health practices early in life, which may eventually lead to an improvement in the overall health status of adults with visual impairments. In view of the higher relative fat levels and lower perceived quality of life values displayed by the women in our study, a greater emphasis should also be placed on improving these health indices in women with visual impairments. Our final recommendation is the need for future studies in this area to document the potential impact of additional factors (such as congenital versus adventitious visual impairment and the impact of various mobility aids) on physical activity levels, body composition, and the perceived quality of life of persons with visual impairments.

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Morbidity and Mortality Weekly Report, 54(SS04), 1–35.

Elizabeth A. Holbrook, M.S., graduate student, Department of Health and Human Performance, Middle Tennessee State University, Campus Box 96, Murfreesboro, TN 37132; e-mail: ⬍eia2a@ mtsu.edu⬎. Jennifer L. Caputo, Ph.D., professor, Department of Health and Human Performance, Middle Tennessee State University; e-mail: ⬍[email protected]⬎. Tara L. Perry, Ph.D., professor, cograduate coordinator, Department of Health and Human Performance, Middle Tennessee State University; e-mail: ⬍tperry@mtsu. edu⬎. Dana K. Fuller, Ph.D., professor, Department of Psychology, Middle Tennessee State University, 1301 East Main Street, P.O. Box 87, Murfreesboro, TN 37132; e-mail: ⬍dkfuller@ mtsu.edu⬎. Don W. Morgan, Ph.D., professor, Department of Health and Human Performance, Middle Tennessee State University; e-mail: ⬍[email protected]⬎.


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