Genotype analysis of noroviruses associated with gastroenteritis outbreaks in childcare centres, Victoria, Australia, 2012-2015.

The characteristics of norovirus outbreaks in children (0-5 years) in childcare centres in Victoria, Australia (2012-2015) were examined. The three most common open reading frame (ORF) 2 genotypes in childcare centre outbreaks were GII.4 (42%), GII.6 (21%) and GII.3 (14%); the remaining genotypes (GI.2, GI.3, GI.4, GI.8, GI.13, GII.1, GII.2, GII.7 and GII.13) each made up <10%. The GII.4 genotype was the only norovirus genotype seen in all 4 years of the study and was the most common genotype in 2012-2014 but in 2015 the most common genotype was GII.2. The GII.4 genotype was more common in children 0-2 years, whereas GII.2 and GII.7 were more common in children 4-5 years. ORF 1/ORF 2 recombinant forms identified were GII.P4_NewOrleans_2009/GII.4_Sydney_2012, GII.P12/GII.3, GII.Pb (GII.21)/GII.3, GII.Pe/GII.2, GII.Pe/GII.4_Sydney_2012 and GII.Pg/GII.1. The findings indicate that norovirus genotype prevalence patterns in children were influenced by the age of the children and the year in which the analysis was carried out. The majority of norovirus infections (84%) occurred after the first year of life so that vaccination before the age of one would appear to be the most efficacious.

Norovirus genotype diversity associated with gastroenteritis outbreaks in aged-care facilities.

Noroviruses are a major cause of gastroenteritis. Vaccine strategies against norovirus are currently under consideration but depend on a detailed knowledge of the capsid genotypes. This study examined the incidence of norovirus outbreaks in residential aged-care facilities in Victoria, Australia over one year (2013) and documented the (capsid) norovirus genotypes associated with these outbreaks. It was found that 65·0% of 206 outbreaks tested were associated with norovirus infection, thereby showing norovirus to be the major cause of viral gastroenteritis in residential aged-care facilities. Fifteen capsid (open reading frame 2) genotypes were identified as follows: GI.2 (0·9%), GI.3 (1·8%), GI.4 (3·7%), GI.6 (0·9%), GI.7 (0·9%), GI.8 (0·9%), GII.1 (0·9%), GII.2 (0·9%), GII.3 (1·8%), GII.4 (2009-like) (0·9%), GII.4 (2012) (48·6%), GII.4 (2012-like) (16·5%), GII.4 (unknown) (9·2%), GII.5 (2·8%), GII.6 (0·9%), GII.7 (0·9%), GII.13 (6·4%) and an as yet unclassified GII genotype (0·9%). Although GII.4 was the most common norovirus capsid genotype detected, the great diversity of norovirus genotypes in the elderly indicates vaccination strategies for this demographic are not straightforward.

Altered patterns of norovirus GII.b recombinant forms in gastroenteritis outbreaks in Victoria, Australia, 2002-2005 compared to 2006-2011.

GII.b norovirus is an obligatory recombinant with an open reading frame (ORF) 1 comprising the GII.b genotype and the ORF 2 region corresponding to one of a number of other norovirus genotypes. GII.b is the second most common genotype after GII.4 associated with gastroenteritis outbreaks in Victoria, Australia. The study involved norovirus testing of 14,186 specimens from 2,743 Victorian gastroenteritis outbreaks in the period 2002-2011. The noroviruses identified were further characterized by nucleotide sequencing and phylogenetic analysis. In the period 2002-2005, 21 GII.b norovirus outbreaks were identified, with the GII.b ORF 2 recombinant genotypes comprising GII.1 (47.6%), GII.3 (47.6%), and GII.13 (4.8%). For the period 2006-2011, 56 GII.b norovirus outbreaks were identified. In 51 of these, the ORF 2 genotype was identified, and comprised GII.1 (2.0%), GII.3 (94.1%), GII.13 (2.0%), and GII.21 (2.0%). GII.b norovirus outbreaks could occur in a range of settings involving individuals with a broad range of ages. However, GII.b/GII.3 norovirus tended to occur in a younger demographic and all outbreaks involving specifically children's settings had the GII.b/GII.3 genotype. Nucleotide sequencing studies demonstrated major changes in both the ORF 1 and ORF 2 regions of the GII.b/GII.3 noroviruses but not in the GII.b/GII.1 and GII.b/GII.13 noroviruses when the noroviruses for the two time periods 2002-2005 and 2006-2011 were compared. The findings suggest nucleotide changes in the pre-existing GII.b/GII.3 noroviruses resulted in a more virulent form.

Insect-inspired AI for autonomous robots.

Autonomous robots are expected to perform a wide range of sophisticated tasks in complex, unknown environments. However, available onboard computing capabilities and algorithms represent a considerable obstacle to reaching higher levels of autonomy, especially as robots get smaller and the end of Moore's law approaches. Here, we argue that inspiration from insect intelligence is a promising alternative to classic methods in robotics for the artificial intelligence (AI) needed for the autonomy of small, mobile robots. The advantage of insect intelligence stems from its resource efficiency (or parsimony) especially in terms of power and mass. First, we discuss the main aspects of insect intelligence underlying this parsimony: embodiment, sensory-motor coordination, and swarming. Then, we take stock of where insect-inspired AI stands as an alternative to other approaches to important robotic tasks such as navigation and identify open challenges on the road to its more widespread adoption. Last, we reflect on the types of processors that are suitable for implementing insect-inspired AI, from more traditional ones such as microcontrollers and field-programmable gate arrays to unconventional neuromorphic processors. We argue that even for neuromorphic processors, one should not simply apply existing AI algorithms but exploit insights from natural insect intelligence to get maximally efficient AI for robot autonomy.

Coccidian oöcysts as type-specimens: long-term storage in aqueous potassium dichromate solution preserves DNA.

Preservation of the exogenous oöcyst stage of coccidian parasites (phylum Apicomplexa N.D. Levine, 1970) as type-specimens of newly described species has long been problematical. Conventional fixatives have proved unsatisfactory, and compromises such as embedding oöcysts in resin or photographing them are not entirely appropriate for various reasons. As an alternative, chilled potassium dichromate solution (normally used in the laboratory to prevent putrefaction of temporary preparations of live oöcysts) has been tested as a long-term preservative of sporulated oöcysts of Eimeria brunetti P.P. Levine, 1942, E. maxima Tyzzer, 1929, E. mitis Tyzzer, 1929, E. necatrix Johnson, 1930, E. praecox Johnson, 1930 and E. tenella (Railliet & Lucet, 1891) (suborder Eimeriorina Léger, 1911; family Eimeriidae Minchin, 1903). Oöcysts from faeces of chickens Gallus gallus (Linnaeus) were placed in 2.5% w/v aqueous potassium dichromate solution (PDS) and stored in the dark at 4 +/- 2 degrees C. After 23 years in storage, oöcysts of each species were administered orally to chickens and failed to initiate infections, indicating that the oöcysts were dead. Nevertheless, after about 24 years, DNA was still recoverable from the oöcysts, and the original species identifications made by classic parasitological methods were confirmed by polymerase chain reaction assays. Furthermore, after almost 25 years, microscopical examination revealed that the walls and internal structures remained well preserved in 83-98% of the oöcysts of the six species investigated. Hence, PDS is potentially suitable for the long-term preservation of sporulated coccidian oöcysts as type-specimens for taxonomic purposes. The samples used in this study are now in the care of the Natural History Museum, London, UK. It is recommended that they be monitored in like manner, by suitably qualified scientists, at intervals of about 5 years to assess their state of preservation and the recoverability of DNA. Enough material is available to monitor it until it is at least 100 years old.

Molecular and epidemiological features of GIIb norovirus outbreaks in Victoria, Australia, 2002-2005.

The epidemiology of GIIb norovirus outbreaks and the characteristics of GIIb open reading frame (ORF) 2 recombinant forms are poorly understood and this study examined these questions using norovirus-associated gastroenteritis outbreaks in Victoria, Australia, during 2002-2005. Twenty-one GIIb outbreaks were detected and were the second most common ORF 1 norovirus outbreak genotype (5%) after GII.4 (90%). Both GIIb and GII.4 outbreaks peaked in warmer months of the year but their periodicity was different. ORF 2 sequencing analysis was carried out in the two regions previously designated C and D. RT-PCR region D primers were less sensitive than region C primers. No evidence of recombination between regions C and D was found. ORF 2 genotypes for the 21 GIIb outbreaks were: GII.1 (10 outbreaks), GII.3 (10 outbreaks) and, apparently for the first time, GII.13 (1 outbreak). GIIb outbreaks could occur in a broad range of settings and there was no correlation between ORF 2 genotype and setting except that all 5 outbreaks involving mainly young children were associated with GIIb/GII.3.

Photochemically Induced Ionic Reactions of Cycloalkenes: Cyclohexenes and cycloheptenes undergo cationic reactions upon ultraviolet irradiation in protic solvents.

Sensitized ultraviolet irradiation of cyclohexenes and cycloheptenes in protic solvents causes reactions which seemingly proceed by way of carbocation intermediates. These intermediates, in turn, may arise from a photochemically produced trans cycloalkene which is so highly strained that protonation by even weak acids such as methanol may proceed readily. This picture is supported by product analysis, deuterium labeling experiments, and stereochemical studies.

A comparative evaluation of the sensitivity of two automated and two manual nucleic acid extraction methods for the detection of norovirus by RT-PCR.

The aim of the study was to compare the sensitivity of a norovirus RT-PCR method using two manual RNA extraction methods (Qiagen and Roche) and two automated RNA extraction methods (Qiagen and Corbett). All four RNA extraction methods gave similar sensitivities although the automated methods, especially the Corbett, required significantly less labour than the manual methods. The automated methods also enabled RNA extraction of approximately two to three times the number of specimens in a given time period compared to manual methods.

Cryptosporidium parvum infection in orphan lambs on a farm open to the public.

A longitudinal survey was undertaken on an open farm to investigate the occurrence of Cryptosporidium species infection in orphan lambs obtained from three local flocks. During an initial pilot study, Cryptosporidium oocysts were detected by a fluorescent antibody test (fat) in the faeces of two of 21 lambs aged between one and three weeks derived from one flock (flock A). Pooled pen samples of faeces were collected weekly from lambs derived from each flock; oocysts were detected by fat in 24 (49.0 per cent) of 49 samples from lambs from flock A, 18 (30.5 per cent) of 59 samples from lambs from flock B and 14 (29.8 per cent) of 47 samples from lambs from flock C. Oocyst counts of 1 x 10(3) to more than 2 x 10(6) per gram of faeces were detected in lambs up to 12 weeks old, with the peak counts occurring at six weeks of age in the lambs from flocks A and B and at four weeks of age in those from flock C. The oocysts were confirmed by molecular analysis as Cryptosporidium parvum. Virtually all the infections were subclinical.

Higher insulin and C-peptide concentrations in Hispanic population at high risk for NIDDM. San Luis Valley Diabetes Study.

Hyperinsulinemia has been demonstrated in Hispanics with normal glucose tolerance and in other populations at higher risk for non-insulin-dependent diabetes mellitus (NIDDM). We compared fasting and glucose-stimulated insulin and C-peptide levels in a community-based sample of 464 Hispanic and 676 non-Hispanic white adult residents of the San Luis Valley of Colorado. All subjects had normal glucose tolerance as confirmed by oral glucose tolerance testing interpreted with World Health Organization criteria. Mean fasting and 1- and 2-h post-glucose load insulin levels were significantly higher in Hispanics versus non-Hispanic whites (fasting 0.08 vs. 0.07 nM, P = 0.0026; 1 h 0.52 vs. 0.47 nM, P = 0.0129; 2 h 0.36 vs. 0.27 nM, P less than 0.0001), even after adjustment for age, sex, body mass index, waist-hip ratio, family history of diabetes mellitus, concurrent plasma glucose level, and fasting insulin level. Mean fasting and 1- and 2-h glucose-stimulated C-peptide levels in Hispanics also significantly exceeded those in non-Hispanic whites (fasting 0.58 vs. 0.54 nM, P = 0.0119; 1 h 2.72 vs. 2.46 nM, P less than 0.0001; 2 h 2.25 vs. 1.97 nM, P less than 0.0001). The C-peptide-insulin molar ratio was greater in non-Hispanic whites than Hispanics at all times measured. These findings confirm that Hispanics with normal glucose tolerance are hyperinsulinemic and that increased insulin secretion is at least partly responsible for this phenomenon. The lower levels of C-peptide compared with insulin in Hispanics suggest that the hyperinsulinemia seen in this ethnic group may be due in part to decreased hepatic insulin extraction.

Prevalence and risk factors of diabetic retinopathy in non-Hispanic whites and Hispanics with NIDDM. San Luis Valley Diabetes Study.

Diabetic retinopathy (DR) is the leading cause of blindness in adults in the United States. Because photocoagulation can reduce the incidence of blindness from severe DR by approximately 50%, it is important to identify people at increased risk for DR so that appropriate treatment can be accomplished. Use of populations at increased risk for diabetes may identify groups at increased risk for complications. A recent report from the San Antonio Heart Study showed that Mexican Americans were at greater risk for servere DR than non-Hispanic Whites. To compare the prevalence of DR between non-Hispanics and Hispanics in southern Colorado, 279 people with non-insulin-dependent diabetes mellitus (NIDDM) were identified, and retinal photographs identified the presence and severity of retinopathy. The worse eye was used to classify the severity of DR for each patient. Ninety percent of the subjects (166 Hispanics and 85 non-Hispanic Whites) were classified by retinopathy level. The duration-adjusted prevalence of any DR was 41.8% in Hispanics and 54.1% in non-Hispanic Whites. Severe DR (preproliferative and proliferative) occurred in 18.5% of the Hispanics and in 21.3% of the non-Hispanic Whites. The odds ratio for any DR, comparing Hispanics with non-Hispanic Whites adjusted for other risk factors, was 0.40 (95% confidence interval = 0.21, 0.76). Other risk factors for the presence of any retinopathy included use of exogenous insulin, increased duration of diabetes, younger age at diagnosis, increased glycosylated hemoglobin level, and increased systolic blood pressure. These data suggest that, compared with non-Hispanic Whites, Hispanics in Colorado may be at decreased risk for diabetic retinopathy.

Dietary fat predicts conversion from impaired glucose tolerance to NIDDM. The San Luis Valley Diabetes Study.

OBJECTIVE: To determine if dietary fat intake measured at a baseline exam in subjects with impaired glucose tolerance (IGT) predicted the subsequent development of non-insulin-dependent diabetes mellitus (NIDDM). RESEARCH DESIGN AND METHODS: Based on an oral glucose tolerance test (OGTT) (World Health Organization criteria), we identified 134 eligible subjects with IGT from a geographically based sample of subjects with no prior history of diabetes. One to three years after the baseline exam, 123 subjects (92%) had a repeat OGTT. Diet was assessed by a 24-h diet recall reported before the baseline OGTT. RESULTS: The mean percentage of energy eaten as fat was 43.4% in 20 people subsequently developing NIDDM compared with 40.6% in 43 people remaining IGT and 38.9% in 60 subjects who subsequently reverted to normal glucose tolerance. In comparing the 20 subjects who developed NIDDM with the 103 who remained IGT or normal, an increase in fat intake of 40 g/day was associated with an increase in risk of NIDDM of 3.4-fold (95% confidence interval [CI] 0.8-13.6) adjusted for energy intake, age, sex, ethnicity, and obesity. The odds ratio increased to sixfold (95% CI 1.2-29.8) after adjustment for fasting glucose, insulin, and 1-h insulin. CONCLUSIONS: Fat consumption significantly predicts NIDDM risk in subjects with IGT after controlling for obesity and markers of glucose metabolism.

Heterogeneity in associations between macronutrient intake and lipoprotein profile in individuals with type 2 diabetes.

OBJECTIVE: To evaluate associations between macronutrient intake and lipoprotein profile among individuals with type 2 diabetes who participated in the San Luis Valley Diabetes Study (SLVDS) or the Insulin Resistance Atherosclerosis Study (IRAS). RESEARCH DESIGN AND METHODS: Diet was assessed by 24-h recall in the SLVDS (n = 421) and by validated food frequency interview in the IRAS (n = 437). Analyses adjusted for kilocalories, age, sex, and other covariates were conducted separately for the two study groups. For the SLVDS, repeated observations were included in mixed model analyses (865 observations). For the IRAS, standard regression analyses were conducted. Recent weight history and time of diabetes diagnosis were evaluated as possible modifiers of associations between nutrient intake and lipoprotein profile. RESULTS: Higher reported intake of total dietary fat was related to significantly higher levels of LDL cholesterol (P < 0.05) in both studies and in all subgroups. Reported intake of total and saturated fat was associated positively with total cholesterol, although statistical significance was not reached for all subgroups. Higher reported carbohydrate intake was associated with increased triglyceride concentrations (P < 0.01) only among individuals with previously undiagnosed diabetes in the SLVDS (n = 69) and only among individuals who gained weight (> 5 lb, n = 87) during the previous year in the IRAS. CONCLUSIONS: Toward the goal of optimizing the lipoprotein profile of individuals with diabetes, these results emphasize the potential importance of reducing fat intake while recognizing that individualized approaches to diet are important to minimize the risk of cardiovascular disease.

Accuracy of reported family history of diabetes mellitus. Results from San Luis Valley Diabetes Study.

There are two possible sources of bias in the assessment of family history of diabetes: 1) a person with diabetes may be more likely to report a diabetic relative than a nondiabetic person would be, and 2) relatives of individuals with diabetes may be more likely to be tested for diabetes than relatives of nondiabetic individuals. We conducted a study on a subsample of families of subjects in the San Luis Valley Diabetes Study to examine these issues. A sample of 5 White and 5 Hispanic subjects (probands) with diabetic glucose tolerance tests and the same number with normal glucose tolerance were selected. The 20 probands all provided contact information on their 227 primary family members. Ninety-two percent of the family members had interviews completed by themselves or, if deceased, by surrogates other than the proband. Family members were asked by telephone if they had ever been tested for diabetes, when they had been most recently tested, why they had been tested, and if they had ever been told they had diabetes. The results showed that study subjects accurately reported family history of diabetes, because there were no discrepancies between proband and family reports. A positive family history of diabetes was associated with increased reported screening in Hispanics, but a similar effect in White families was not seen. Women were also more likely to report being screened than men regardless of whether there was a positive family history of diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between habitual physical activity and insulin levels among nondiabetic men and women. San Luis Valley Diabetes Study.

OBJECTIVE: To determine whether higher levels of physical activity would be associated with lower fasting insulin and C-peptide levels in a free-living nondiabetic population. RESEARCH DESIGN AND METHODS: A cross-sectional study was conducted with a Hispanic and non-Hispanic white population of 442 men and 489 women with normal glucose tolerance (by World Health Organization criteria) in two rural Colorado counties. Total physical activity was assessed by a 7-day physical activity recall from which metabolic equivalents were estimated. Relationships between metabolic equivalents and fasting insulin and C-peptide were assessed while considering obesity, age, and other risk factors known to influence fasting insulin levels. RESULTS: Among all subjects, univariate analyses showed that higher activity levels were associated with lower mean fasting insulin and C-peptide levels (P less than or equal to 0.05). Multiple linear regression showed that higher activity was significantly associated with lower values of log fasting insulin and C-peptide levels in men only (P less than 0.001) independent of obesity, fat distribution, and age. Men in the highest tertile of activity had an adjusted mean fasting insulin level of 59.2 pM and fasting C-peptide level of 0.5 nM compared with a fasting insulin level of 72.7 pM and fasting C-peptide level of 0.6 mM for men in the lowest tertile of activity. The magnitude of the inverse association between activity and insulin was greatest in older rather than younger men. Physical activity was not associated with fasting insulin or C-peptide levels in women in the multivariate analyses. CONCLUSIONS: Based on cross-sectional data, we conclude that higher levels of habitual physical activity are associated with lower fasting insulin and C-peptide levels in Hispanic and non-Hispanic white men.

Microvascular complications of NIDDM in Hispanics and non-Hispanic whites. San Luis Valley Diabetes Study.

The goal of this article was to examine the differences in the rates of microvascular complications of non-insulin-dependent diabetes mellitus (NIDDM) in Hispanic and non-Hispanic white subjects. This was a geographically based case-control study where prevalent cases of NIDDM were identified in medical records. Subjects attended a 4-h clinic to confirm NIDDM diagnosis and assess complication end points. Retinopathy was defined by stereofundus photographs. Distal symmetric neuropathy was determined by standardized clinical examination. Nephropathy was indicated by serum creatinine level, urine protein-creatinine ratio, and urine albumin concentration. This study consisted of 279 NIDDM subjects confirmed by oral glucose tolerance test and World Health Organization criteria aged 20-74 yr (187 Hispanic and 92 non-Hispanic white subjects). Duration-adjusted prevalence of retinopathy was significantly higher in non-Hispanic white subjects (54.1 per 100, 95% confidence interval [CI] 44.4-63.7) than in Hispanics (41.8 per 100, 95% CI 34.8-48.8). This excess occurred only in non-Hispanic white subjects with background retinopathy but not in those with more severe retinopathy. Hispanics and non-Hispanic white subjects did not differ significantly for the prevalence of neuropathy (31.6 per 100 in non-Hispanic white subjects and 26.3 per 100 in Hispanics) or nephropathy by any measure. There were no significant differences in duration of diabetes or mean glycohemoglobin levels between ethnic groups. Microvascular complications of NIDDM are not in excess among Colorado Hispanics, and retinopathy may be somewhat more common in non-Hispanic white people.

Blood pressure, insulin, and C-peptide levels in San Luis Valley, Colorado.

OBJECTIVE: To explore the associations between blood pressure and both fasting insulin and C-peptide levels. RESEARCH DESIGN AND METHODS: A cross-sectional analysis was conducted of 895 normoglycemic members of a bi-ethnic community in Colorado who were selected from a control group recruited for a geographically based study of diabetes mellitus prevalence and risk factors. All subjects included in this study had normal glucose tolerance as judged by a 75-g oral glucose tolerance test interpreted using World Health Organization criteria. None of the subjects were taking antihypertensive medication. Multiple linear regression analysis was used to examine relationships between fasting insulin and C-peptide levels and blood pressure. RESULTS: Among all subjects, diastolic blood pressure was found to significantly increase with increasing levels of both hormones (insulin coefficient = 0.197, P = 0.013; C-peptide coefficient = 0.0436, P = 0.004), whereas systolic blood pressure was significantly related to fasting C-peptide level (coefficient = 0.0295, P = 0.050). These relationships were similar in magnitude for both Hispanic and non-Hispanic white subjects, but were diminished among women and subjects with a higher body mass index. CONCLUSIONS: Higher fasting insulin and C-peptide levels are associated with higher blood pressure, but these relationships are modified by sex and degree of obesity.

Reproductive history, glucose tolerance, and NIDDM in Hispanic and non-Hispanic white women. The San Luis Valley Diabetes Study.

OBJECTIVE: To ascertain whether childbearing would decrease oral glucose-stimulated insulin and C-peptide levels and increase the risk of NIDDM and impaired glucose tolerance in a population of Hispanic and non-Hispanic white women residing in the San Luis Valley of Colorado. Several investigators have related childbearing to subsequent abnormal glucose tolerance. RESEARCH DESIGN AND METHODS: In a population-based case-control epidemiological study, diabetic patients 20-74 yr of age (n = 196) and randomly sampled control women subjects (n = 735) underwent a glucose tolerance test, a physical examination, and an in-person standardized interview. The relations between the live-birth number and fasting and oral glucose stimulated glucose, insulin and C-peptide concentrations, and NIDDM and impaired glucose tolerance were estimated using linear or logistic regression to adjust for extraneous variables. RESULTS: In women selected as control subjects, the live-birth number was related to a significant decrease in the sum of 1- and 2-h C-peptide concentrations (coefficient = -0.077, P < 0.001) and the logarithm of the sum of 1- and 2-h insulin concentrations (coefficient = -0.014, P = 0.02). After adjustment for subscapular skin-fold thickness, the relative odds of NIDDM for the live-birth number, which was small and of borderline significance, diminished (odds ratio = 1.04 for one birth, P = 0.18). Findings were similar for impaired glucose tolerance. CONCLUSIONS: Childbearing was related to lower C-peptide and insulin levels in Hispanic and non-Hispanic women of the San Luis Valley. It had little apparent effect on later risk of NIDDM or impaired glucose tolerance.

Improving power with repeated measures: diet and serum lipids.

The inability to detect associations between diet and serum cholesterol in cross-sectional population studies has been attributed to measurement error in diet assessments and between-subject variability in lipid concentrations. Current statistical methods can reduce the effects of measurement error and allow within-subject comparisons when replicate measures on individuals are available, even if the time between replicates is as long as 4 y and replicate data are not available for all subjects. Data from 928 nondiabetic participants of the San Luis Valley Diabetes Study with measures of 24-h dietary intake and fasting lipid concentrations at baseline, at a 4-y follow-up visit, or both were analyzed in a random-effects model that allowed for an unbalanced design. Sex was included as a non-time-varying covariate and age, body mass index, and energy intake were included as time-varying covariates. The findings when LDL cholesterol (mmol/L) was regressed on saturated fat intake (20 g/d) with all observations in a random-effects model (beta = 0.14, P = 0.0016) were compared with results with observations restricted to the first visit only (beta = 0.05, P = 0.52), a balanced design using averages across visits (beta = -0.12, P = 0.28), and a balanced design with random effects obtained by excluding subjects without two observations (beta = 0.12, P = 0.0092). Study power was greatest in the random-effects model using all observations and time-varying covariates. These findings highlight the importance of even a single replicate observation on a subsample of subjects. We recommend analyzing all data rather than averaging measures across visits or omitting observations to create a balanced design.

Associations between dietary factors and serum lipids by apolipoprotein E polymorphism.

A geographically based observational study of 852 nondiabetic Hispanic and non-Hispanic white persons in southern Colorado aged 20-74 y was conducted to determine whether diet-lipid associations were modified by the apolipoprotein E (apoE, protein; APOE, gene) polymorphism. Subjects were seen for up to three visits from 1984 to 1992. A 24-h diet recall was collected and fasting serum lipid concentrations were measured at all visits. In longitudinal-regression analyses, dietary factors were significantly associated with serum lipid concentrations in the directions expected based on the large amount of literature on this topic. The positive relation between dietary cholesterol and serum total and low-density-lipoprotein cholesterol was strongest in Hispanic subjects with the APOE*2 allele (E2/ 2,3/2 genotypes) and non-Hispanic white subjects with the APOE*3 allele (E3/3 genotype), and there was no association in subjects with the APOE*4 allele (E4/3, 4/4 genotypes) in either ethnic group. No other statistically significant differences in the relations between dietary factors and serum lipid concentrations by APOE polymorphism were identified. These findings suggest that the APOE polymorphism plays only a minor role in modifying the association between dietary factors and serum lipids.