In the current study, data regarding the influence of physical activity counseling on habitual physical activity level and mobility outcomes, in both diabetic and non-diabetic older persons, have been presented. Based on the results of this study, the primary findings were:
(1) Physical activity counseling does not improve diabetics’ habitual physical activity level or mobility; however, it can help diabetics maintain current levels of mobility, by preventing decline in 2 km walking ability. (2) Physical activity counseling influences more change among non-diabetics than it does among diabetics, in regards to both habitual physical activity level and mobility outcomes..
In the present study, physical activity counseling was not an effective method for improving mobility or increasing habitual physical activity in diabetics. Diabetics in the intervention group showed no significant changes in maximal walking speed, 2 km walking ability, or habitual physical activity level. This finding is supported by existing literature, which suggests that diabetics experience additional difficulty maintaining physical activity regimens (Ahola & Groop 2013; Colberg & Sigal 2011; Foreyt & Poston 1999). However, previous studies also indicate that physical activity counseling can significantly improve habitual physical activity in diabetic subjects (Avery et al. 2012). While diabetics in the intervention group demonstrated no significant change over the follow-up period, diabetics in the control group showed significant decline in 2 km walking ability. This contrast suggests that, while physical activity counseling may not improve diabetics’ mobility, it may serve to protect diabetics from mobility decline.
The observed association between physical activity counseling and decreased mobility loss in diabetics is weakly supported in the existing literature. Since improved glycemic control is the main outcome measure in most physical activity counseling studies for diabetics, no studies with mobility-specific outcome measures could be located. However, poor glycemic control has been linked to mobility disability – in the National Health And Nutrition Examination Survey cohort, diabetics were 2.06 times as likely to experience
lower extremity mobility disability, with 10% of diabetics’ excess risk being attributable to poor glycemic control (Kalyani et al. 2010). This suggests that physical activity counseling’s directional influence on mobility loss can be minimally inferred based on its influence on glycemic control. Studies have shown statistically significant improvements in HbA1c among diabetics receiving physical activity counseling (Avery et al. 2012;
Plotnikoff et al. 2011). Therefore, physical activity counseling may ultimately decrease mobility loss in aging diabetics, through positive effects on glucose management.
However, it should be noted that studies of physical activity counseling among diabetics, using mobility indicators as primary outcome measures, are needed in order to definitively determine the relationship between physical activity counseling and mobility loss within the older diabetic population.
The current study also suggests that the effectiveness of physical activity counseling is lessened in diabetic populations as opposed to non-diabetic populations. While diabetics in the intervention group showed no significant change in outcome measures, non-diabetics in the intervention group showed significant improvements in both maximal walking speed and habitual physical activity. Furthermore, diabetes status was shown to significantly impact within- and between-subject change in maximal walking speed over the follow-up period. Studies examining the differential effects of physical activity counseling according to diabetes status could not be located in the literature, which complicates validation of these findings. However, the diminution of physical activity counseling’s effectiveness in diabetics does make intuitive sense, given (1) the exceptional difficulty that diabetics experience when trying to maintain physical activity regimens, and (2) the increased prevalence of and tendency toward sedentary lifestyle among diabetics (Avery et al. 2012;
Colberg & Sigal 2011; Foreyt & Poston 1999).
The strengths of the present study are largely due to the design of the original SCAMOB trial. The inclusion of a control group theoretically allowed for the approximation of longitudinal change in the absence of the intervention. However, given the significant improvements in the non-diabetic control group, control conditions in this study were likely violated by unintentional activation of control subjects and by information flow across
randomization groups (Rasinaho et al. 2011). During functional assessments, the single-blinded design prevented differential treatment of the randomization and control groups by researchers. Additionally, the well-characterized randomization helped to reduce demographic differences between study groups and minimize selection bias. Furthermore, the longer-than-average follow-up time contributed to a more accurate estimation of long-term changes in physical activity and mobility.
Having examined the intervention characteristics best suited for diabetics, it appears that the SCAMOB intervention had considerable potential for promoting physical activity among diabetics. By incorporating the behavioral concepts of social cognitive theory and the trans-theoretical model, the SCAMOB intervention provided a platform for the promotion of long-term behavioral change through empowerment and self-efficacy.
Additionally, the involvement of health professionals throughout the screening, counseling, and exercise processes served to maximize safety for diabetics. Since nurses initially screened all participants for cardiovascular health, visual difficulties, and impaired sensation in the feet, it is unlikely that any diabetics were accidentally recommended physical activity regimens that were contraindicated by diabetic complications.
Furthermore, the utilization of telephone follow-up served as a convenient, low-cost method for promoting long-term adherence in diabetic subjects, who generally require additional supervision. (Leinonen et al. 2007)
The highly individualized nature of the SCAMOB intervention could either enhance or decrease the suitability of the intervention for diabetics, depending on the options selected.
Since participants were counseled based on stated preferences, it is possible that selected activities differed significantly from general activity recommendations for diabetics.
Additionally, given that ADA and ACSM guidelines were not used to formulate diabetics’
activity plans, it is unlikely that their plans reflected the rigorous specifications of these guidelines. (Leinonen et al. 2007, Colberg et al. 2010)
Despite the probability that diabetic participants did not follow ADA and ACSM physical activity guidelines, the SCAMOB intervention could still benefit the older diabetic
population. Although the present study indicated minimal effectiveness for physical activity counseling among diabetics, the SCAMOB intervention could potentially influence small changes in diabetics’ physical activity, which could later serve as a foundation for measurable increases in physical activity. Numerous studies state the importance of promoting gradual increases in physical activity, since these are (1) more likely to be maintained and (2) more effective for improving self-efficacy (Ahola & Groop 2013;
Foreyt & Poston 1999; Sigal et al. 2006) Diabetics often begin with below-average fitness levels, so the SCAMOB intervention could serve as a crucial first step for long-term DSM through physical activity (Colberg & Sigal 2011).
The weaknesses of the present study are considerable, and primarily result from the limitations inherent to secondary analyses. Data were not collected with the present analysis in mind, so the resultant dataset was not well suited for a comparison of diabetic and non-diabetic populations. The small number of diabetics within the sample significantly impaired statistical analysis, in numerous ways. Firstly, the small number of diabetics relative to non-diabetics significantly affected the homogeneity of baseline characteristics between groups, as evidenced by statistically significant differences in years of education and maximal walking speed at baseline. Secondly, since the diabetic subgroups had sample sizes less than 30, it is unlikely that tests for independence were robust enough to compensate for abnormal distributions in the diabetic groups. Inadequate sampling most likely contributed to the statistical insignificance of findings in diabetics, since similar changes resulted in statistically significant findings for the more populous non-diabetic groups. Lastly, the small diabetic sample size affected nonparametric analysis by contributing to violations of assumed minimum expected cell frequency in transition tables. In order for p-values from marginal homogeneity tests to be valid, at least 80% of cells in the table should have counts greater than or equal to 5. However, inadequate sampling of diabetics resulted in violations of this assumption in tables 3 and 4, most likely affecting the validity of statistical tests performed for these analyses.
Additionally, the methods used to discern diabetes status in the SCAMOB study are not optimal for the present analysis. Definitive determination of diabetes status was not
essential to initial study aims, so diabetes status was only defined by self-report. For the present study, in which diabetes status is of primary importance, this is problematic, mainly due to the high prevalence of undiagnosed diabetes. In Finland, approximately 250,000 people are known to have T2DM, but it is estimated that an additional 200,000 Finns have undiagnosed T2DM (FDA 2012). For this reason, it is likely that some of the individuals in the non-diabetic groups were actually diabetic.
The method used to define diabetes is also problematic because it does not differentiate between T1DM and T2DM. Since this study focuses on T2DM, contamination of the sample with type 1 diabetics would be problematic. However, contemporary estimates of diabetes prevalence in Finland indicate that the number of type 1 diabetics in the sample is most likely negligible. Registry data indicate that, as of 2002, 74% of known diabetes cases in Finland were of type 2, while type 1 and unknown type accounted for only 13%
each. Furthermore, the average age of diabetic participants was 77.57 ± 2.08 years in 2003;
in 2002, there were only 42 known cases of T1DM nationwide among Finns aged 75-79.
Since this number represents only 0.2% of diabetes cases in the 75-79 age bracket, it is not likely that type 1 diabetics represent a significant proportion of diabetics in the study.
(Niemi & Winell 2006)
10 CONCLUSION
The primary findings of this study are as follows: (1) Physical activity counseling does not improve diabetics’ habitual physical activity level or mobility; however, it can help diabetics maintain current levels of mobility, by preventing decline in 2 km walking ability.
(2) Physical activity counseling influences more change among non-diabetics than it does among diabetics, in regards to both habitual physical activity level and mobility outcomes..
These findings suggest that, although physical activity counseling for diabetics may not be effective at reversing mobility loss, it can still effectively prevent mobility loss in this population. Additionally, these findings suggest that diabetics require additional intervention in order to achieve equal improvements in habitual physical activity and mobility outcome measures. Directions for future research include similar analyses in a more suitable sample, as well as the investigation of supplementary intervention strategies for the reversal of mobility loss in older diabetics.
11 REFERENCES
Ahola, A. J., & Groop, P.-H. 2013. Barriers to self-management of diabetes. Diabetic Medicine 30, 413-420.
Albu, J., & Pi-Sunyer, F. X. 1998. Obesity and diabetes. In: Bray G. A., Bouchard C. &
James W. P. T. (ed.) Handbook of Obesity. Marcel Dekker Inc., New York, 697-707.
American Diabetes Association. 2003. Peripheral arterial disease in people with diabetes.
Diabetes Care 26, 3333-3341.
American Diabetes Association. 2012. Diagnosis and classification of diabetes mellitus.
Diabetes Care 35, S64-S71.
Anderson, R. M., Funnell, M. M., Barr, P. A., Dedrick, R. F., & Davis, W. K. 1991.
Learning to empower patients. Diabetes Care 14, 584-590.
Anderson, R. M., Funnell, M. M., Nwankwo, R., Gillard, M. L., Fitzgerald, J. T., & Oh, M.
2001. Evaluation of a problem-based, culturally specific, patient education program for African Americans with diabetes (abstract). Diabetes 50, A195.
Anderson, R. M., Funnell, M. M., & Hernandez, C. A. 2005. Choosing and using theories in diabetes education research. Diabetes Educator 31, 513, 515, 518-520.
Araki, A., Iimuro, S., Sakurai, T., Umegaki, H., Iijima, K., Nakano, H., et al. 2012. Long-term multiple risk factor interventions in Japanese elderly diabetic patients: The Japanese elderly diabetes intervention trial – study design, baseline characteristics and effects of intervention. Geriatrics & Gerontology International 12, 7-17.
Avery, L., Sniehotta, F. F., Flynn, D., Trenell, M. I., & van Wersch, A. 2012. Changing physical activity behavior in type 2 diabetes: A systematic review and meta-analysis of behavioral interventions. Diabetes Care 35, 2681-2689.
De Backer, G., Ambrosioni, E., Borch-Johnsen, K., Brotons, C., Cifkova, R., Dallongeville, J., et al. 2003. European guidelines on cardiovascular disease prevention in clinical practice: Third joint task force of European and other societies on cardiovascular disease prevention in clinical practice (constituted by representatives of eight
societies and by invited experts). European Journal of Cardiovascular Prevention &
Rehabilitation 10, S1-S10.
Balducci, S., Iacobellis, G., Parisi, L., Di Biase, N., Galandriello, E., Leonetti, F., &
Fallucca, F. 2006. Exercise training can modify the natural history of diabetic peripheral neuropathy. Journal of Diabetes Complications 20, 216-223.
Bandura, A. 1977. Self-efficacy: Toward a unifying theory of behavioral change.
Psychological Review 84, 191-215.
Beisswenger, P. J. 2012. Glycation and biomarkers of vascular complications of diabetes.
Amino Acids 42, 1171-1183.
Van der Bij, A. K., Laurent, M. G. H., Wensing, M. 2002. Effectiveness of physical activity interventions for older adults. American Journal of Preventive Medicine 22, 120-133.
Bijnen, F. C. H., Feskens, E. J. M., Caspersen, C. J., Mosterd, W. L., & Kromhout, D.
1998. Age, period, and cohort effects on physical activity among elderly men during 10 years of follow-up: The Zutphen elderly study. The Journals of Gerontology Series A: Biological Sciences & Medical Sciences 53A, M235-M241.
Von Bonsdorff, M. B. 2009. Physical activity as a predictor of disability and social and health service use in older people. Ph.D. Thesis. University of Jyväskylä. Studies in Sport, Physical Education, & Health 141. ISSN 0356-1070.
Bruce, D. G., Casey, G. P., Grange, V., Clarnette, R. C., Almeida, O. P., Foster, J. K., Ives, F. J., & Davis, T. M. E. 2003. Cognitive impairment, physical disability and depressive symptoms in older diabetic patients: The Fremantle cognition in diabetes study. Diabetes Research & Clinical Practice 61, 59-67.
Bryhni, B., Jenssen, T. G., Olafsen, K., & Eikrem, J. H. 2003. Age or waist as determinant of insulin action? Metabolism 52, 850-857.
Catalano, K. J., Bergman, R. N., & Ader, M. 2005. Increased susceptibility to insulin resistance associated with abdominal obesity in aging rats. Obesity Research 13, 11-20.
Centers for Disease Control and Prevention. 2011. National Diabetes fact Sheet 2011 (Publication No. CS217080A). http://www.cdc.gov/diabetes/pubs/pdf/ndfs_2011.
pdf . 05.05.2012.
Chen, M., Bergman, R. N., Pacini, G., & Porte, D., Jr. 1985. Pathogenesis of age-related glucose intolerance in man: Insulin resistance and decreased beta-cell function.
Journal of Clinical Endocrinology & Metabolism 60, 13-20.
Colberg, S. R., Sigal, R. J., Fernhall, B., Regensteiner, J. G., Blissmer, B. J., Rubin, R. R., Chasan-Taber, L., Albright, A. L., Braun, B., American College of Sports Medicine,
& American Diabetes Association. 2010. Exercise and type 2 diabetes – The American College of Sports Medicine and the American Diabetes Association: Joint position statement. Diabetes Care 33, E147-E167.
Colberg, S. R., & Sigal, R. J. 2011. Prescribing exercise for individuals with type 2 diabetes: Recommendations and precautions. Physician and Sportsmedicine 39, 13-26.
Conn, V. S., Minor, M. A., Burks, K. J., Rantz, M. J., Pomeroy, S. H. 2003. Integrative review of physical activity intervention research with aging adults. Journal of the American Geriatrics Society 51, 1159-1168.
Coyne, K. S., Margolis, M. K., Kennedy-Martin, T., Baker, T. M., Klein, R., Paul, M. D., Revicki, D. A. 2004. The impact of diabetic retinopathy: Perspectives from patient focus groups. Journal of Family Practice 21, 447-453. doi:
10.1093/fampra/cmh417
Cress, M. E., Schechtman, K. B., Mulrow, C. D., Fiatarone, M. A., Gerety, M. B., &
Buchner, D. M. 1995. Relationship between physical performance and self-perceived physical function. Journal of the American Geriatrics Society 43, 93-101.
Elder, G. H., Jr., Kirkpatrick-Johnson, M., & Crosnoe, R. 2003. The emergence and development of life course theory. In: Mortimer J. & Shanahan M. (ed.) Handbook of the Life Course. Kluwer Academic Publishers, New York, 3-19.
Estacio, R. O., Regensteiner, J. G., Wolfel, E. E., Jeffers, B., Dickenson, M., & Schrier, R.
W. 1998. The association between diabetic complications and exercise capacity in NIDDM patients. Diabetes Care 21, 291-295.
Figaro, M. K., Kritchevsky, S. B., Resnick, H. E., Shorr, R. I., Butler, J. B., Shintani, A., Penninx, B. W., Simonsick, E. M., Goodpaster, B. H., Newman, A. B., Schwartz, A.
V., & Harris, T. B. 2006. Diabetes, inflammation, and functional decline in older
adults: Findings from the health, aging and body composition (ABC) study.
Diabetes Care 29, 2039-2045.
Finnish Diabetes Association. 2012. Diabetes in Finland. http://www.diabetes.fi/en/
finnish_diabetes_association/diabetes_in_finland. 01.04.2013.
Folstein, M. F., Folstein, S. E., & McHugh, P. R. 1975. Mini-mental state: A practical method for grading the cognitive state of patients for the clinician. Journal of Psychiatric Research 12, 189-198.
Foreyt, J. P., & Poston, C. 1999. The challenge of diet, exercise and lifestyle modification in the management of the obese diabetic patient. International Journal of Obesity 23, S5-S11.
Freedman, V. A. 2009. Adopting the ICF language for studying late-life disability: A field of dreams? Journals of Gerontology Series A: Biological Sciences & Medical Sciences 64A, 1172-1174.
De Fronzo, R. A. 1981. Glucose intolerance and aging. Diabetes Care 4, 493-501.
Funnell, M. M., & Anderson, R. M. 2004. Empowerment and self-management of diabetes. Clinical Diabetes 22, 123-127.
The Futurage Project. 2011. Futurage: A road map for European ageing research (European Commission project No. FP7-HEALTH-2007-B/No 223679).
http://futurage.group.shef.ac.uk/assets/files/Final%20road%20map/FUTURAGE%2
0A%20Road%20Map%20for%20European%20Ageing%20Research%20-%20October%202011.pdf. 01.05.2012.
Gill, T. M., Robison, J. T., & Tinetti, M. E. 1998. Difficulty and dependence: Two components of the disability continuum among community-living older persons.
Annals of Internal Medicine 128, 96-101.
Gong, Z., & Muzumdar, R. H. 2012. Pancreatic function, type 2 diabetes, and metabolism in aging. International Journal of Endocrinology 2012, Article ID 320482. doi:
10.1155/2012/320482
Goraya, T. Y., Leibson, C. L., Palumbo, P. J., Weston, S. A., Killian, J. M., Pfeifer, E. A., Jacobsen, S. J., Frye, R. L., & Roger, V. L. 2002. Coronary atherosclerosis in diabetes mellitus: A population-based autopsy study. Journal of the American College of Cardiology 40, 946-953.
Green, B. B., McAfee, T., Hindmarsh, M., Madsen, L., Caplow, M., & Buist, D. 2002.
Effectiveness of telephone support in increasing physical activity levels in primary care patients. American Journal of Preventive Medicine 22, 177-183.
Gregg, E. W., Beckles, G. L. A., Williamson, D. F., Leveille, S. G., Langlois, J. A., Engelgau, M. M., & Narayan, K. M. V. 2000. Diabetes and physical disability among older U.S. adults. Diabetes Care 23, 1272-1277.
Gugliucci, A. 2000. Glycation as the glucose link to diabetic complications. Journal of the American Osteopathic Association 100, 621-634.
Gulve, E. A. 2008. Exercise and glycemic control in diabetes: Benefits, challenges, and adjustments to pharmacotherapy. Physical Therapy 88, 1297-1321. doi:
10.2522/ptj.20080114
Guralnik, J. M., Branch, L. G., Cummings, S. R., & Curb, J. D. 1989. Physical performance measures in aging research. Journal of Gerontology: Medical Sciences 44, M141-M146.
Guralnik, J. M., & Ferrucci, L. 2009. The challenge of understanding the disablement process in older persons. Journals of Gerontology Series A: Biological Sciences &
Medical Sciences 64A, 1169-1171. doi: 10.1093/gerona/glp094
Hales, C. N., Barker, D. J. P., Clark, P. M. S., Cox, L. J., Fall, C., Osmond, C., & Winter, P. D. 1991. Fetal and infant growth and impaired glucose tolerance at age 64.
British Medical Journal 303, 1019-1022.
Hales, C. N., & Barker, D. J. P. 1992. Type 2 (non-insulin-dependent) diabetes mellitus:
The thrifty phenotype hypothesis. Diabetologia 35, 595-601.
Hales, C. N., & Barker, D. J. P. 2001. The thrifty phenotype hypothesis. British Medical Bulletin 60, 5-20.
Hamann, C., Stephan, K., Guenther, K. P., & Hofbauer, L. C. 2012. Bone, sweet bone – osteoporotic fractures in diabetes mellitus. Nature Reviews Endocrinology 8, 297-305.
Van der Heide, L. P., Ramakers, G. M. J., Smidt, M. P. 2006. Insulin signaling in the central nervous system: Learning to survive. Progress in Neurobiology 79, 205-221.
Hoeymans, N., Feskens, E. J. M., van den Bos, G. A. M., & Kromhout, D. 1996.
Measuring functional status: Cross-sectional and longitudinal associations between performance and self-report (Zutphen elderly study 1990-1993). Journal of Clinical Epidemiology 49, 1103-1110.
Hogan, D. P., & Goldscheider, F. K. 2003. Success and challenge in demographic studies of the life course. In: Mortimer J. & Shanahan M. (ed.) Handbook of the life course. Kluwer Academic Publishers, New York 681-691.
Home, P. 2003. The challenge of poorly controlled diabetes mellitus. Diabetes &
Metabolism 29, 101-109.
Hu, F. B., Stampfer, M. J., Solomon, C., Liu, S.,Colditz, G. A., Speizer, F. E., Willett, W.
C., & Manson, J. E. 2001. Physical activity and risk for cardiovascular events in diabetic women. Annals of Internal Medicine 134, 96-105.
Iijima, K., Iimuro, S., Ohashi, Y., Takashi, S., Umegaki, H., Araki, A., Yoshimura, Y., Ouchi, Y., Ito, H., & the Japanese Elderly Diabetes Intervention Trial Study Group.
2012. Lower physical activity, but not excessive calorie intake, is associated with metabolic syndrome in elderly with type 2 diabetes mellitus: The Japanese elderly diabetes intervention trial. Geriatrics & Gerontology International 12, 68-76. doi:
10.111/j.1447-0594.2011.00814.x
Institute of Medicine. 2007. The Future of Disability in America. The National Academies Press, Washington, D.C.
International Diabetes Federation. 2011. IDF Diabetes Atlas, 5th ed. International Diabetes Federation, Brussels.
International Diabetes Federation. 2012. IDF Diabetes Atlas, 5th ed.: 2012 Update.
International Diabetes Federation, Brussels.
Imbeault, P., Prins, J. B., Stolic, M., Russell, A. W., O’Moore-Sullivan, T., Després, J.-P., Bouchard, C., & Tremblay, A. 2003. Aging per se does not influence glucose homeostasis: In vivo and in vitro evidence. Diabetes Care 26, 480-484.
Iozzo, P., Beck-Nielsen, H., Laasko, M., Smith, U., Yki-Jarvinen, H., & Ferrannini, E.
1999. Independent influence of age on basal insulin secretion in nondiabetic humans: European group for the study of insulin resistance. Journal of Clinical Endocrinology & Metabolism 84, 863-868.
Jancey, J. M., Lee, A. H., Howat, P. A., Clarke, A., Wang, K., & Shilton, T. 2008. The effectiveness of a physical activity intervention for seniors. American Journal of Health Promotion 22, 318-321.
Jette, A. M. 1994. Physical disablement concepts for physical therapy research and practice. Physical Therapy 74, 380-386.
Jette, A. M. 2009. Toward a common language of disablement. Journals of Gerontology Series A: Biological Sciences & Medical Sciences 64A, 1165-1168. doi:
10.1093/gerona/glp093
Kalyani, R. R., Saudek, C. D., Brancati, F. L., & Selvin, E. 2010. Association of diabetes, comorbidities, and A1C with functional disability in older adults: Results from the national health and nutrition examination survey (NHANES), 1999-2006. Diabetes Care 33, 1055-1060.
Keene, G. S., Parker, M. J., & Pryor, G. A. 1993. Mortality and morbidity after hip-fractures. British Medical Journal 307, 1248-1250.
King, A. C., Rejeski, W. J., & Buchner, D. M. 1998. Physical activity interventions
King, A. C., Rejeski, W. J., & Buchner, D. M. 1998. Physical activity interventions