E. Dryson

Serum 25-hydroxyvitamin D3 levels decreased in impaired glucose tolerance and diabetes mellitus

A cross-sectional survey was carried out in a New Zealand Polynesian and Caucasian workforce of 5677 staff aged 40-64 years to determine whether serum concentrations of 25-hydroxyvitamin D3 are altered in people with newly diagnosed diabetes mellitus and impaired glucose tolerance (IGT). Serum 25-hydroxyvitamin D3 concentration was significantly lower in newly detected cases with diabetes and IGT (n = 238) compared with controls individually matched by sex, age (+/- 2 years), ethnicity, and date of interview (mean (S.D.): 69 (31) vs. 76 (34) nmol/l; P = 0.0016). Among controls, serum concentrations were significantly lower in Maori (mean (S.E.) = 65 (5) nmol/l; P = 0.0013) and Pacific Islanders (59 (4) nmol/l; P = 0.0001) compared with Europeans (82 (3) nmol/l), after adjusting for age, sex, and time of year. We conclude that diabetes and IGT are associated with low serum concentrations of 25-hydroxyvitamin D3 and that low concentrations of this hormone in New Zealand Polynesians may partly explain their increased prevalence of diabetes/IGT compared with Europeans.

Microalbuminuria in a Middle-Aged Workforce: Effect of hyperglycemia and ethnicity

OBJECTIVE To determine the prevalence of microalbuminuria in a mixed, thnic population and to find the extent that ethnic variation in microalbuminuria can be explained by abnormal glucose metabolism, obesity, hypertension, hypertriglyceridemia, and life-style factors. RESEARCH DESIGN AND METHODS Urinary albumin concentrations were measured in 5467 middle-aged Maori, Pacific Islander, and European workers who participated in a health-screening survey of 46 New Zealand companies. Participants provided a first-voided, morning urine sample; had a 75-g oral glucose tolerance test; had weight, height, and blood pressure measured; and completed a self-administered questionnaire about past medical history and sociodemographic status. RESULTS A significantly higher prevalence of microalbuminuria was found in individuals with new cases of diabetes mellitus (24.1%), in cases of diabetes mellitus previously diagnosed (20.6%), and in those with impaired glucose tolerance (16.1%) compared with nondiabetic individuals (4.0%). Moreover, in the general population, a piecewise linear relationship was detected between albuminuria and plasma glucose with significant changes of slope corresponding with 2 h plasma glucose concentrations (95% confidence interval) of 6.7 (6.4–7.0) and 9.2 (8.6–9.8) mM, respectively. After adjusting for sex, obesity, hypertension, hypertriglyceridemia, cigarette smoking, and heavy alcohol consumption in a multivariate model, glycemia was the most significant determinant of urinary albumin concentrations in all three ethnic groups. However, blood glucose concentrations did not completely explain the higher relative risk (95% confidence interval) of microalbuminuria in Maori (5.97; 4.48–7.78) and Pacific Islander (5.33; 4.13–6.87) workers compared with European workers. CONCLUSIONS Of the variables investigated, hyperglycemia was the most important factor explaining the high prevalence of microalbuminuria in Maori and Pacific Islander workers compared with the European workers. However, only 14.9% of the variation in urinary albumin concentrations was found in our multivariate model, and we have speculated on the contribution of other factors such as diet and coexisting renal diseases.

Serum 25-hydroxycholecalciferol concentration in newly detected hypertension†

Although blood concentrations of the active metabolite 1,25-dihydroxyvitamin D are raised in hypertension, concentrations of 25-hydroxyvitamin D, the main vitamin D metabolite, do not appear to have been reported in newly detected hypertension. Serum levels of 25-hydroxycholecalciferol were measured in 186 newly detected hypertensive patients (blood pressure > 160/95 mm Hg and never on antihypertensive medication) and normotensive controls individually matched by sex, age (+/- 2 years), ethnicity, and date of interview. Serum 25-hydroxycholecalciferol levels were similar in cases (mean (SD) = 64 (21) nmol/L) and controls (67 (28) nmol/L, P = .20). We conclude that serum 25-hydroxycholecalciferol, a marker of body vitamin D, is normal in hypertension.

Reproducibility and validity of a food frequency questionnaire in European and polynesian New Zealanders

The reproducibility and validity of a self-administered 142-item food-frequency questionnaire (FFQ) was assessed in a population comprising 124 European and 52 Polynesian (17 Maori and 35 Pacific Island) New Zealanders aged 40-65 years. Reproducibility correlation coefficients, determined by administration of the same questionnaire on two occasions 3 years apart, were higher in European than Maori and Pacific Island participants, ranging from 0.47 to 0.87 in Europeans (median 0.66) and from 0.41 to 0.79 in Maori and Pacific Island people (median 0.44). In general, there were no significant differences in mean nutrient intakes calculated from the two FFQs by Europeans or Maori and Pacific Island participants despite their cultural and language differences. When the FFQ was compared with a 3-day food diary in a subsample of 101 Europeans, 15 Maori and 22 Pacific Islanders, the validity was good for most nutrients, with overestimation of a few nutrients in each ethnic group. Correlation coefficients between the 3-day food diary and FFQ ranged from 0.41 to 0.81 in Europeans (median 0.48) and from 0.36 to 0.56 in Maori and Pacific Island people (median 0.55). Ratios of energy intake to resting metabolic rate suggested that Maori and Pacific Island people were more likely to underestimate their habitual energy intake by the 3-day diet diary method compared to Europeans, but that Europeans were more likely to underestimate total energy intake by the food frequency method and Pacific Island participants to overestimate it. Obese Europeans and Maori were more likely to under-report dietary intakes by the 3-day diary method. We conclude that our FFQ performed better in European than Maori and Pacific Island participants.

Diabetes Mellitus and Employment: Is there Discrimination in the Workplace?

The employment record of 102 diabetic workers (73 men, 29 women), identified in a cross‐sectional survey of 5670 middle‐aged people in a New Zealand workforce, was studied for evidence of discrimination in the workplace. Compared with 403 matched controls (292 men, 111 women), diabetic workers showed no significant differences in socioeconomic status, educational attainment, or distribution between occupational groups. Similarly, mean duration of current employment (12.3 vs 12.4 years), mean number of jobs in the past 5 years (1.25 vs 1.34 jobs), frequency of sickness absence, and mean number of hours worked each week (43.5 vs 43.3h) did not differ significantly between diabetic and non‐diabetic groups. We found no significant differences in work stress, even among those diabetic individuals with poor blood glucose control. There was no convincing evidence across a broad spectrum of industry that diabetic workers did suffer discrimination in the workplace.

Diabetes mellitus and employment: survey of a New Zealand workforce.

A cross‐sectional survey of a 5670 multiracial New Zealand workforce aged >40 years was used to determine the health status of people with diabetes mellitus in employment. One hundred and two workers (73 men, 29 women) had known diabetes mellitus (prevalence of 1.8%) of whom 91 individuals (89.2%) had Type 2 diabetes. Mean age of diabetic workers was 51.1 ± 5.6 (SD) years and median duration of disease was 5.0 (range 0–51) years. Most subjects were asymptomatic, although only 31.4% of diabetic workers had fasting glucose concentrations and 35.5% had fructosamine concentrations within the mean ± 2SD range of a matched control group. Moreover, 22.5% of diabetic participants had fasting hypertriglyceridaemia and 21.6% had microalbuminuria. Ethnicity (non‐European vs European) and lack of insulin therapy were the most important predictors of poor glycaemic control. We advocate more aggressive therapy with insulin and with culturally sensitive education programmes to avert long‐term macrovascular complications.