Bridgette J. McNamara

Type 2 diabetes in Indigenous populations: Quality of intervention research over 20 years

BACKGROUND A robust evidence base is needed to reduce the disproportionately high rates of diabetes-related mortality and complications among Indigenous peoples. OBJECTIVE This study aimed to evaluate the quantity and methodological quality of published intervention research on Type 2 and gestational diabetes in the Indigenous populations of Australia, Canada, New Zealand, and the United States from 1989 to 2008. A robust evidence base is needed to reduce the disproportionately high rates of diabetes-related mortality and complications among Indigenous peoples. METHODS Systematic searches of Medline, Embase, and EBM Reviews identified publications focused on Type 2 or gestational diabetes in Indigenous peoples published between 1 January 1989 and 31 December 2008. Total publication number and proportion of research involving interventions over time were examined. The quality of intervention studies was evaluated using Cochranes Effective Practice and Organisation of Care (EPOC) criteria. RESULTS Total publication number increased significantly over the 20 years (p<0.004). Research was predominantly descriptive (87%), with the proportion of research involving interventions increasing from 3% in 1989-1993 to 12% in 2003-2008 (χ(2)=12.42, df=3, p=0.006). However, only 25% (95%CI: 9-41%) of intervention studies met the EPOC methodological quality criteria; other studies lacked sufficient controls or measurements over time. CONCLUSIONS Increases in the amount of high-quality intervention research for prevention and treatment of Type 2 and gestational diabetes among Indigenous populations of these countries are needed.

Renal pathology, glomerular number and volume in a West African urban community

BACKGROUND Low glomerular number and large glomerular volume are hypothesized to be risk factors for hypertensive renal disease in adult life. Reports of human glomerular number are based on studies from developed nations and have found single kidney mean values of approximately 900 000 per kidney with a roughly 8-fold range matched by a similar range in glomerular volume. Glomerular number and volume have never been investigated in people from a developing country. METHODS This study analysed the pathology of 81 autopsy kidneys from Dakar, Senegal, and determined total glomerular number and mean glomerular volume in 28 of these kidneys using the physical disector/fractionator method. RESULTS Total glomerular number ranged 2.6-fold from 536 171 to 1 394 010, with a mean of 925 485 nephrons. The mean glomerular volume was 5.74 microm(3) x 10(6) with a 2.5-fold variation that was strongly and inversely correlated with total glomerular number. Glomerular number was inversely correlated with age, and age-associated increases in arteriosclerosis, cortical fibrosis and glomerulosclerosis were observed. Arteriolar nephrosclerosis was observed in 34% of adults. Mean glomerular number in this Dakar population was similar to that previously reported for people from developed nations, while the range of glomerular number and mean glomerular volume was much narrower. CONCLUSIONS The frequency of arteriolar nephrosclerosis in these Senegalese adults was high (34%), suggesting that hypertensive kidney disease could contribute to a large burden of future chronic kidney disease in this population. Unusually low glomerular number or large glomerular volume do not appear to provide a basis for this potential burden of kidney disease.

Diabetes in pregnancy among indigenous women in Australia, Canada, New Zealand and the United States: a systematic review of the evidence for screening in early pregnancy

Recently proposed international guidelines for screening for gestational diabetes mellitus (GDM) recommend additional screening in early pregnancy for sub‐populations at a high risk of type 2 diabetes mellitus (T2DM), such as indigenous women. However, there are criteria that should be met to ensure the benefits outweigh the risks of population‐based screening. This review examines the published evidence for early screening for indigenous women as related to these criteria. Any publications were included that referred to diabetes in pregnancy among indigenous women in Australia, Canada, New Zealand and the United States (n = 145). The risk of bias was appraised. There is sufficient evidence describing the epidemiology of diabetes in pregnancy, demonstrating that it imposes a significant disease burden on indigenous women and their infants at birth and across the lifecourse (n = 120 studies). Women with pre‐existing T2DM have a higher risk than women who develop GDM during pregnancy. However, there was insufficient evidence to address the remaining five criteria, including the following: understanding current screening practice and rates (n = 7); acceptability of GDM screening (n = 0); efficacy and cost of screening for GDM (n = 3); availability of effective treatment after diagnosis (n = 6); and effective systems for follow‐up after pregnancy (n = 5). Given the impact of diabetes in pregnancy, particularly undiagnosed T2DM, GDM screening in early pregnancy offers potential benefits for indigenous women. However, researchers, policy makers and clinicians must work together with communities to develop effective strategies for implementation and minimizing the potential risks. Evidence of effective strategies for primary prevention, GDM treatment and follow‐up after pregnancy are urgently needed. Copyright

Diabetes in pregnancy among indigenous women in Australia, Canada, New Zealand and the United States.

Recently proposed international guidelines for screening for gestational diabetes mellitus (GDM) recommend additional screening in early pregnancy for sub‐populations at a high risk of type 2 diabetes mellitus (T2DM), such as indigenous women. However, there are criteria that should be met to ensure the benefits outweigh the risks of population‐based screening. This review examines the published evidence for early screening for indigenous women as related to these criteria. Any publications were included that referred to diabetes in pregnancy among indigenous women in Australia, Canada, New Zealand and the United States (n = 145). The risk of bias was appraised. There is sufficient evidence describing the epidemiology of diabetes in pregnancy, demonstrating that it imposes a significant disease burden on indigenous women and their infants at birth and across the lifecourse (n = 120 studies). Women with pre‐existing T2DM have a higher risk than women who develop GDM during pregnancy. However, there was insufficient evidence to address the remaining five criteria, including the following: understanding current screening practice and rates (n = 7); acceptability of GDM screening (n = 0); efficacy and cost of screening for GDM (n = 3); availability of effective treatment after diagnosis (n = 6); and effective systems for follow‐up after pregnancy (n = 5). Given the impact of diabetes in pregnancy, particularly undiagnosed T2DM, GDM screening in early pregnancy offers potential benefits for indigenous women. However, researchers, policy makers and clinicians must work together with communities to develop effective strategies for implementation and minimizing the potential risks. Evidence of effective strategies for primary prevention, GDM treatment and follow‐up after pregnancy are urgently needed. Copyright

A comparison of nephron number, glomerular volume and kidney weight in Senegalese Africans and African Americans

BACKGROUND Low nephron number is determined in utero and is a proposed risk for essential hypertension. Glomerular volume is inversely correlated with nephron number, and genetic and environmental factors that determine nephron number are thought to determine glomerular volume. This study compared total glomerular (nephron) number (N(glom)), mean glomerular volume (V(glom)) and kidney weight in two geographically separated black populations with significant common genetic ancestry. METHODS Unbiased stereology was used to determine N(glom) and V(glom) in kidneys collected at coronial autopsy in an age- and sex-matched sample of 39 adult Africans from Dakar in Senegal, West Africa and 39 African Americans from Mississippi in the USA. RESULTS African Americans were taller and heavier than their Senegalese counterparts. N(glom) was remarkably similar-with a geometric mean of 937 967 in Senegalese and 904 412 in African Americans (P = 0.62). V(glom) was correlated inversely with N(glom) and directly with body surface area in both groups, but V(glom) was 54% greater in African Americans than in Senegalese Africans [8.30 +/- 2.92 (SD) and 5.38 +/- 1.25 microm(3) x 10(6), respectively] and remained significantly larger (38%) after adjustment for body size. V(glom) increased with age in African Americans, but not in the Senegalese. Kidney weight was larger in African Americans (P < 0.0001), but kidney-to-body weight ratio was not different between groups. CONCLUSIONS Despite similar nephron numbers, a common genetic constitution, and even in relation to current body size, African Americans have larger V(glom) than Senegalese subjects. This may mark exposure to environmental stressors or hereditary traits concentrated in the populations relocation to North America.

Distribution of Volumes of Individual Glomeruli in Kidneys at Autopsy: Association with Physical and Clinical Characteristics and with Ethnic Group

We have demonstrated considerable variability in the volumes of different glomeruli in given individuals (individual glomerular volume: IGV) in a stereologic study of kidneys at forensic autopsy performed to investigate sudden or unexpected death in people without manifest kidney disease. We review some important associations of IGV by subject characteristics and by ethnic groups. IGVs were measured by the Cavalieri method in 30 glomeruli in each of 111 adult males who belonged to 4 ethnic groups, i.e. US Whites, African-Americans, Africans from Senegal, and Australian Aborigines. Correlations of pooled IGV values with certain subject characteristics were evaluated in the US Whites. Pooled IGV data were compared in subjects across the 4 ethnic groups. In US Whites, mean IGV and its variance were greater with higher age, lower nephron number, lower birth weight, and with gross obesity, hypertension and cardiovascular death. In comparisons by ethnic group, mean IGV and IGV ranges were higher in African-Americans and Australian Aborigines than in US Whites and African Senegalese subjects. We conclude that glomerular enlargement with volume heterogeneity marks more advanced age, relative nephron deficiency, lower birth weight, obesity, hypertension, and advanced cardiovascular disease. The findings in African-Americans and Australian Aborigines suggest that larger IGVs and volume heterogeneity might mark populations with accentuated susceptibility to hypertension and kidney disease, but the data need to be further examined in the context of the determining characteristics defined in the US Whites.

Associations between age, body size and nephron number with individual glomerular volumes in urban West African males

BACKGROUND Glomerulomegaly has been associated with an increased risk of renal disease. Few reports have investigated the heterogeneity of glomerular size within kidneys and associated risk factors. This study measured the individual glomerular volume (IGV) of 720 non-sclerotic glomeruli in kidneys of adult West African males, and investigated associations of IGV with age, total glomerular (nephron) number and body surface area (BSA). METHODS IGVs were determined in the kidneys of 24 Senegalese males from two age groups (12 subjects aged 20- 30 years and 12 subjects aged 50-70 years). Subjects were randomly chosen at autopsies performed at Le Dantec Hospital in Dakar. Volumes of 30 glomeruli per subject were determined using the disector/Cavalieri stereological method. RESULTS IGVs ranged from 1.31 x 10(6) microm3 to 12.40 x 10(6) microm3 (a 9.4-fold variation). IGV varied up to 5.3-fold within single kidneys. The trimmed range of IGV within subjects (10th to 90th percentile of IGV) was directly correlated with median glomerular size. The mean and standard deviation (SD) of IGV did not differ significantly between age groups or between subjects with higher (> or =1.78 m2) and lower BSA (<1.78 m2). In older subjects the SD of IGV was significantly and directly correlated with BSA. Kidneys with less than 1 million nephrons had significantly larger mean IGV than kidneys with more than 1 million nephrons, and the trimmed range of IGVs within subjects was inversely correlated with total glomerular number. CONCLUSION There was a considerable variation in IGV within kidneys of Senegalese males at autopsy. The heterogeneity of IGV was increased in association with low nephron number and increased BSA, with more pronounced effects in older subjects.

Measuring psychological distress in older Aboriginal and Torres Strait Islanders Australians: a comparison of the K-10 and K-5.

Objectives: To assess the cross‐cultural validity of two Kessler psychological distress scales (K‐10 and K‐5) by examining their measurement properties among older Aboriginal and Torres Strait Islanders and comparing them to those in non‐Aboriginal individuals from NSW Australia.

Design-based stereological methods for estimating numbers of glomerular podocytes

The podocyte depletion hypothesis has emerged as a unifying concept in glomerular pathology. According to this hypothesis podocyte depletion may be absolute (decrease in number of healthy mature podocytes), relative (fewer podocytes per unit of glomerular volume) or involve alterations to the specialized podocyte architecture (such as foot process effacement). To study and understand podocyte depletion it is important to be able to accurately and precisely count these cells. Here we present new design-based stereological methods for estimating podocyte number in individual glomeruli of known volume, and in average glomeruli. Both methods involve serial histological sectioning, triple label immunohistochemistry, laser confocal microscopy and cell counting with the optical disector/fractionator.

Modern and traditional diets for Noongar infants

Aim:  Describe breast‐ and bottle‐feeding patterns and the introduction of solid feeds and sugar containing drinks to the dietary intake of a cohort of urban Aboriginal infants in the first year of life.