Prevalence and Risk Factors for Neuropathy in a Canadian First Nation Community
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Pathophysiology/Complications ORIGINAL ARTICLE Prevalence and Risk Factors for Neuropathy in a Canadian First Nation Community 1 SHARON G. BRUCE, PHD Limited information exists on diabe- 2 T. KUE YOUNG, MD, DPHIL tes foot complications in Canadian First Nation populations. Depending on case definition, estimates of neuropathy range OBJECTIVE — The purpose of this study was to determine the prevalence of and risk factors from 12% among a pediatric population for diabetic neuropathy in a Canadian First Nation population. to 46% among adults (9–12). Hanley et al. (10) reported the prevalence of neu- RESEARCH DESIGN AND METHODS — This was a community-based screening ropathy to be 46% among adult members study of 483 adults. Measures included glucose, A1C, cholesterol, triglycerides, homocysteine, of the Sandy Lake First Nation (northern hypertension, waist circumference, height, weight, and foot examinations. Neuropathy was Ontario), with neuropathy being defined defined as loss of protective sensation determined through application of a 10-g monofilament. as a score of Ն2 on a modified Michigan RESULTS — Twenty-two percent of participants had a previous diagnosis of diabetes, and Neuropathy Screening Instrument. Reid 14% had new diabetes or impaired fasting glucose (IFG). The prevalence of neuropathy in- et al. (11) performed foot examinations, creased by glucose level: 5% among those with normal glucose levels, 8% among those with new interviews, and chart reviews on a sample IFG and diabetes, and 15% among those with established diabetes (P Ͻ 0.01). Those with (139 of 322) of individuals with diabetes neuropathy were more likely to have foot deformities (P Ͻ 0.01) and callus (P Ͻ 0.001) than in one northern Manitoba First Nation those without neuropathy. Among those with dysglycemia (Ն6.1 mmol/l), the mean number of community and found that 82% had foot problems for those with insensate feet was 3 compared with 0.3 among those with sensation some form of diabetes-related foot prob- Ͻ (P 0.001). In multivariate logistic regression female sex, low education, A1C, smoking, and lem. The average number of foot prob- homocysteine were independently associated with neuropathy, after controls for age. lems per individual was three. CONCLUSIONS — Neuropathy prevalence is high, given the young age of our participants Neuropathy was found among 24% of (mean 40 years) and was present among those with undiagnosed diabetes. The high number and participants, past or present foot ulcer in type of foot problems places this population at increased risk for ulceration; the low level of foot 15%, and 3% had had an amputation. care in the community increases the risk. Homocysteine is a risk factor that may be related to Chuback et al. (12) completed chart re- lifestyle and requires further investigation. views, interviews, and examinations on 110 Aboriginal attendees at an urban pe- Diabetes Care 31:1837–1841, 2008 diatric diabetes clinic in Manitoba and found a high prevalence of foot abnormal- iabetes-related foot complications foot ulcer (6). Of these, the most impor- ities (age range of participants was 12–17 are an increasingly common yet tant contributory factor for foot ulcer- years). Neuropathic symptoms (numb- D understudied problem (1) and ation is peripheral neuropathy; when ness, aching, and tingling) were found in include conditions such as neuropathy, neuropathy is absent, ulceration is rare 12% of participants. These results are foot deformities, ulcers, and lower- (5,7). It is estimated that 80% of foot ul- especially disturbing, considering the extremity amputation. The impact of cers may be prevented through early de- short duration of diabetes in this pediat- diabetes-related foot complications on tection (5). Screening for neuropathy has ric population. quality of life and health care costs is therefore been identified as an effective The study community reported in significant, especially for ulcers and strategy in the prevention process (8). this article belongs to a tribal council for amputation (2–4). The lifetime risk for The purpose of this research was to deter- which the rate of diabetes-related ampu- foot ulceration among those with diabe- mine the prevalence and determinants of tation (6.2 per 1,000) is twice as great as tes is 15% (5,6), and foot ulceration pre- diabetic neuropathy in a Canadian First that for other First Nations people in the cedes amputation in 80% of patients (5). Nation community that has a significantly province (3.1 per 1,000) and 30 times The major risk factors for diabetic foot greater rate of diabetes-related amputa- greater than the rate for non–First Nations ulceration are peripheral neuropathy, pe- tion than that for the general population people in the province (0.19 per 1,000) ripheral vascular disease, and previous (9). (9). Thus, diabetes-related foot problems are emerging as a serious complication of ●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●● diabetes among First Nations people of From the 1Department of Community Health Services, University of Manitoba, Winnipeg, Manitoba, Can- Canada. We undertook a screening study ada; and the 2Department of Public Health Services, University of Toronto, Toronto, Ontario, Canada. Corresponding author: Sharon Bruce, [email protected]. in a community with a high rate of ampu- Received 6 February 2008 and accepted 19 May 2008. tation to determine the burden of neurop- Published ahead of print at http://care.diabetesjournals.org on 28 May 2008. DOI: 10.2337/dc08-0278. athy and to initiate secondary prevention © 2008 by the American Diabetes Association. Readers may use this article as long as the work is properly strategies. cited, the use is educational and not for profit, and the work is not altered. See http://creativecommons. The data for this article are from a org/licenses/by-nc-nd/3.0/ for details. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby larger screening study for diabetes and di- marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. abetes complications conducted in 2003 DIABETES CARE, VOLUME 31, NUMBER 9, SEPTEMBER 2008 1837 Neuropathy in a First Nation community among adult members of the Sandy Bay cholesterol was measured by a direct en- RESULTS — Table 1 contains demo- First Nation. Sandy Bay First Nation is zymatic method (Boehringer Mannheim). graphic and health risk information. Men located in Manitoba, Canada. The com- LDL was calculated via the following for- and women were equally represented. munity is located about 200 km from mula but not on samples that had visible The sample was representative of the eli- Winnipeg, the nearest major urban cen- chylomicrons or triglycerides Ͼ4.52 gible adult community population for age ter, and is accessible by road year-round. mmol/l: and sex (Table 2). The level of employ- The on-reserve population as of Decem- ment is low for both sexes. Women were ber 2001 was 2,968, of which 35% are ϭ significantly more likely than men to re- aged Ͻ18. LDL cholesterol total cholesterol port having completed at least grade 9. Ϫ HDL cholesterol Ϫ (0.46 The majority of participants were current RESEARCH DESIGN AND smokers. Mean pack-years smoked was METHODS — As part of a larger ϫ triglycerides) about 8 for both sexes. Approximately screening study for diabetes and diabetes 40% of men and women have hyperten- complications, all nonpregnant commu- sion. Although obesity is a major problem Ն Apolipoproteins A and B were mea- nity members aged 18 years were in- sured by the Beckman APA and APB tests, in both men and women, the problem is vited to participate. A total of 483 respectively (Beckman Array Systems). significantly greater among women (15). community members participated, 36% Of the participants, 29% had diabetes; 7% ϭ Quantitative determination of APA and of all eligible adults (n 1,356). Full foot APB was completed by rate nephelome- (35 of 483) were new diagnoses, and 22% examinations were completed for 467 try. Total fasting homocysteine was de- (105 of 483) had a previous diagnosis of participants. termined by high-performance liquid diabetes upon entry to the study. A fur- chromatography with fluorometric ther 7% were found to have IFG. No sig- Assessment of neuropathy detection. nificant differences in glycemic status Neuropathy was defined as the loss of Hypertension. Hypertension was de- were found between men and women. protective sensation determined through Ͼ The mean age of those with dysglycemia fined systolic blood pressure 140 Ϯ application of the 10-g Semmes- mmHg or diastolic blood pressure Ͼ90 (44.51 11.97 years) was significantly Weinstein monofilament wire system. greater than for those with normal glu- mmHg or a previous diagnosis with Ϯ Ͻ Using a standardized questionnaire, a reg- medications. cose values (34.01 10.77 years; P istered nurse ascertained experience of 0.001), with dysglycemia being defined Anthropometric measures. Height, Ն foot pain, numbness, and tingling and weight, and waist and hip circumferences as FBG 6.1 mmol/l or previous diagno- then completed a foot examination for de- were measured using standard tech- sis of diabetes. formities, calluses, preulcers, ulcers, toe- niques (14). nail integrity, and amputation. After this Smoking. Current and past smoking sta- examination, the nurse applied the mono- tus and number of cigarettes smoked per Neuropathy filament to 10 sites on the foot. Partici- day were determined using a standard- Neuropathic foot problems by glycemic pants who were unable to sense the ized questionnaire. Pack-years was calcu- status are listed in Table 3. Overall, 34 monofilament on one or more sites were lated as number of packs per day (one participants (7%) had neuropathy. A sig- defined as insensate (13). Individuals pack ϭ 20 cigarettes) multiplied by num- nificant progression in symptom occur- who had a previous foot ulcer (n ϭ 1) or rence is noted for all categories of ϭ ber of years smoked.