Heterogeneous case definitions used for the surveillance of influenza in Europe

We reviewed the case definitions used by 21 influenza sentinel-based surveillance networks in Western Europe. Two clinical syndromes were used with a wide range of case definitions that nevertheless shared common criteria. Although there is currently no international consensus, efforts are being undertaken to standardise influenza case definitions in Europe.

Respiratory infections in infants: interaction of parental allergy, child care, and siblings-- The PIAMA study

OBJECTIVE

To investigate the association between contacts with other children and the development of respiratory infections in the first year of life in children with or without genetic predisposition for allergy.

METHODS

Children (n = 4146) who participate in a prospective birth cohort study (Prevention and Incidence of Asthma and Mite Allergy study) were investigated. Questionnaires were used to obtain information on doctor-diagnosed upper respiratory tract infection (URTI) and lower respiratory tract infection (LRTI), child care attendance, having siblings, family history of allergic disease, and various potential confounders.

RESULTS

Child care attendance in the first year of life was associated with doctor-diagnosed URTI (adjusted odds ratio [AOR]: 2.7; 95% confidence interval [CI]: 2.1-3.4 for large child care facility vs no child care) and doctor-diagnosed LRTI (AOR: 5.6; 95% CI: 3.9-7.9). Having siblings was associated with doctor-diagnosed LRTI (AOR: 2.6; 95% CI: 2.0-3.4). In addition, children who have allergic parents and attend child care or have older siblings have a higher risk of developing doctor-diagnosed LRTI than do children who have nonallergic parents.

CONCLUSIONS

Child care attendance or having siblings increases the risk of developing doctor-diagnosed LRTI in the first year of life to a greater extent in allergy-prone children than in children who are not allergy prone.

Results of molecular detection of Mycoplasma pneumoniae among patients with acute respiratory infection and in their household contacts reveals children as human reservoirs

During a 30-month prospective study in The Netherlands, the distribution of Mycoplasma pneumoniae and respiratory viruses among 1172 patients with acute respiratory infection (ARI) who were treated in the outpatient general practitioner setting was studied. M. pneumoniae, as detected by polymerase chain reaction analysis, was present in 39 (3.3%) patients. The infection rate was similar in all age groups. Nose and throat samples collected from 79 household contacts of M. pneumoniae-positive index patients revealed M. pneumoniae in 12 (15%) cases. The frequency of M. pneumoniae among household contacts of index patients treated with appropriate antibiotics and untreated index patients was similar. Nine of the 12 M. pneumoniae-positive household contacts were <16 years old (P=.02), and 4 (44%) of them did not develop ARI. Apparently, children are a relevant reservoir for M. pneumoniae.

Cost-effectiveness analysis of pneumococcal vaccination for elderly individuals in The Netherlands

OBJECTIVE

To assess the cost effectiveness (net costs per life year gained) of pneumococcal vaccination of elderly individuals aged 65 years and over in The Netherlands.

DESIGN AND SETTING

A pharmacoeconomic analysis was conducted from the healthcare perspective in The Netherlands. The gender- and age-specific modelling framework linked epidemiological aspects of invasive pneumococcal disease (e.g. incidence, mortality, life years lost) to vaccination and hospital resource use. To derive 90% confidence limits for net costs per life year gained a stochastic analysis was performed.

INTERVENTION

Pneumococcal vaccination in the elderly with the 23-valent vaccine. Effectiveness of the vaccine in preventing invasive pneumococcal disease was derived from international studies.

MAIN OUTCOME MEASURES AND RESULTS

Pneumococcal vaccination in the elderly was not found to be cost saving. At baseline, stochastic and univariate sensitivity analysis net costs per life year gained were estimated to be between 6000 and 16,000 euro (EUR) [EUR1 = 1.1 US dollars; cost level 1995]. A scenario analysis on alternative age-dependent vaccination strategies indicated even higher net costs per life year gained, up to EUR28,000 for vaccinating only those elderly aged 85 years and over.

CONCLUSIONS

Pneumococcal vaccination is associated with net costs per life year gained of EUR10,100 (at baseline assumptions). These costs are higher than those for influenza vaccination (EUR5500). Our pharmacoeconomic approach, which needs to be considered in conjunction with social, psychological and budgetary issues, is intended to contribute to rational decision-making in healthcare policy.

Pharmacoeconomics of influenza vaccination in the elderly: reviewing the available evidence

Most western countries have influenza vaccination programmes for citizens aged > or = 65 years. This paper reviews the available evidence on whether elderly influenza vaccination is worthwhile from a pharmacoeconomic point of view. A search on Medline and EMBASE resulted in a primary selection of approximately 100 studies on the pharmacoeconomics of influenza vaccination in the elderly. Further selection of studies to be included in the review was based on several criteria such as original research paper, cost-benefit or cost-effectiveness analysis. influenza vaccination in the elderly, and publication between 1980 and 1999. The 10 studies included in the final selection were evaluated regarding 3 main aspects: benefit-cost ratio and cost-effectiveness ratio; vaccine effectiveness; and relative costing of the vaccine. In general, differences in benefit-cost ratios could be explained by differences in effectiveness and relative costing of the vaccine. Considering the available pharmacoeconomic evidence, influenza vaccination of the elderly in western countries is an intervention with favourable cost-effectiveness in terms of net costs per life-year gained and even has cost-saving potential. In particular, influenza vaccination among elderly people at higher risk, such as the chronically ill elderly, is generally found to be cost saving. Relatively favourable cost-effectiveness among non-high-risk elderly justifies universal influenza vaccination of the elderly from a pharmacoeconomic point of view.

Effect of consumption of uncooked (RS2) and retrograded (RS3) resistant starch on apparent absorption of magnesium, calcium, and phosphorus in pigs

The aim of this investigation was to study the effect of uncooked (RS2) and retrograded (RS3) resistant starch on the size and site of the apparent absorption of magnesium, calcium, and phosphorus in swine. In an experiment with a parallel design, three groups of six piglets each consumed for two weeks a diet containing either glucose, RS2 or RS3. The piglets were cannulated at the end of the ileum which allowed estimation of the ileal and colonic mineral absorption. Urine, feces, and ileal digesta were collected for measurement of magnesium, calcium, and phosphorus. Dietary RS2, but not RS3, versus glucose reduced (p < 0.05) the total absorption of magnesium and calcium and the ileal absorption of phosphorus in the pig. Differences between species or in RS and/or mineral intake may explain why RS2 reduced the apparent absorption of magnesium and calcium in pigs in this study and raised it in rats in earlier studies.

Limited effect of consumption of uncooked (RS2) or retrograded (RS3) resistant starch on putative risk factors for colon cancer in healthy men

To investigate whether resistant starch (RS) affects putative risk factors for colon cancer, 24 healthy men consumed a daily RS supplement for 4 wk in addition to their habitual diet in a single-blind, randomized, balanced multiple crossover trial. During the first week, all subjects consumed the control supplement containing glucose. Subsequently, each subject consumed, in random order, a supplement with RS2 (uncooked high-amylose cornstarch), RS3 (extruded and retrograded high-amylose cornstarch), and glucose, each for 1 wk. The RS2 and RS3 supplements provided 32 g RS/d. Lithium was added to the supplements to measure compliance. Feces, 24-h urine, and breath samples, as well as a 24-h food-consumption recall were obtained weekly from each subject. Compliance as measured by urinary lithium recovery was satisfactory. The mean composition of the background diet did not differ between the various supplementation periods. Breath-hydrogen excretion, stool weight, and fecal starch excretion were significantly higher during RS than during glucose supplementation, but did not differ during RS2 and RS3 supplementation. There were no significant differences in fecal dry weight, pH, or short-chain fatty acid concentrations, nor in the pH, bile acid concentrations, cytotoxicity, or osmolality of fecal water. It is concluded that in healthy men, supplementing the habitual diet for 1 wk with 32 g RS2 or RS3/d compared with glucose had no effect on putative risk factors for colon cancer, except for increasing stool weight and colonic fermentative activity. There were no significant differences between the effects of RS2 and RS3 on the indexes studied.

Consumption of retrograded (RS3) but not uncooked (RS2) resistant starch shifts nitrogen excretion from urine to feces in cannulated piglets

To study the effect of resistant starch (RS) on the route of nitrogen excretion, we fed three groups of six cannulated piglets each a diet containing either uncooked resistant starch (RS2 ), retrograded resistant starch (RS3 ) or glucose. The use of piglets with a cannula at the end of the ileum allowed measurement of the amount of nitrogen that entered the colon. Ileal digesta, urine and feces were collected quantitatively and weighed, and dry matter, starch and nitrogen content were determined. We hypothesized that RS2 would lower colonic absorption of nitrogen when compared with RS3 , because RS2 may be more fermentable than RS3 , thus trapping more nitrogen in bacteria. The piglets fed RS3 had a significantly higher production of ileal digesta and feces than the piglets fed glucose or RS2 . In the piglets fed RS2 , 44% of the amount of RS fed was recovered in the ileal digesta; in the piglets fed RS3 , 71% was recovered. Thus, more fermentable material entered the colon in the RS3 -fed piglets than in the RS2 -fed piglets. Virtually no starch was recovered in the feces of any dietary group. Replacement of glucose by either RS2 or RS3 did not affect nitrogen retention but increased fecal nitrogen excretion. Compared with glucose, RS3 but not RS2 reduced urinary nitrogen excretion, mainly in the form of urea, and reduced the amount of nitrogen absorbed by the colon when expressed as a percentage of the amount of nitrogen entering the colon. This study provides evidence that RS3 , but not RS2 , shifts nitrogen excretion from urine to feces in cannulated piglets.

Neither raw nor retrograded resistant starch lowers fasting serum cholesterol concentrations in healthy normolipidemic subjects

The question addressed was whether dietary resistant starch would lower serum cholesterol and triacylglycerol concentrations in healthy normolipidemic subjects. In a randomized single-blind 3 x 3 Latin-square study with corrections for any carryover effects, 27 males and 30 females consumed supplements containing glucose or resistant starch (RS) from raw high-amylose cornstarch (RS2) or from retrograded high-amylose cornstarch (RS3). The RS2 and RS3 supplements provided 30 g RS/d. Each type of supplement was consumed in addition to the habitual diet for 3 wk. At the end of each 3-wk period, fasting blood samples and a 24-h food-consumption recall were obtained from each subject. The subjects collected 24-h urine samples for lithium determination, which was added to the supplements to check compliance. Mean lithium recovery was 97% and did not differ between supplements. The mean composition of the background diet was similar when the three supplements were taken. Body weight remained constant throughout the study. There were no significant differences in the fasting concentrations of serum total, high-density-lipoprotein (HDL), and low-density-lipoprotein (LDL) cholesterol; triacylglycerols, or 3 alpha-hydroxy bile acids after consumption of glucose, RS2, or RS3. Evidence is presented that the lack of effect of RS2 and RS3 on serum lipid concentrations cannot be explained by insufficient statistical power, a low dose, or a short duration of treatment. The subjects reported softer stools and more gastrointestinal symptoms after supplementation with RS than after glucose. Neither the RS2 nor the RS3 supplements lowered serum lipid concentrations in healthy, normolipidemic men and women.

Dietary raw versus retrograded resistant starch enhances apparent but not true magnesium absorption in rats

Dietary raw (RS2) vs. retrograded resistant starch (RS3) raises apparent magnesium absorption in rats. The mechanism proposed is that RS2 enhances magnesium avaibility for absorption; it does this by increasing ileal solubility of magnesium due to a reduction in pH as a consequence of RS2 fermentation in the gut. The mechanism implies that dietary RS2 vs. RS3 would raise true magnesium absorption and stimulate reabsorption of endogenous magnesium, leading to a lower fecal excretion of endogenous magnesium. Dietary lactulose vs. glucose raises apparent magnesium absorption, and the mechanism proposed is similar to that for the stimulatory effect of RS2 vs. RS3. Thus, we measured in rats fed RS3, RS2, glucose or lactulose true magnesium absorption on the basis of the retention of the orally and intraperitoneally administered radiotracer 28Mg. Feeding rats RS2 instead of RS3 significantly enhanced apparent but not true magnesium absorption, because RS2 lowered fecal excretion of endogenous magnesium. When compared with dietary glucose, lactulose significantly raised both apparent and true magnesium absorption, but did not affect fecal excretion of endogenous magnesium. It is suggested that the proposed mechanism by which RS2 and lactulose would enhance magnesium absorption is disproved by the present data.

Resistant starch has little effect on appetite, food intake and insulin secretion of healthy young men

OBJECTIVE

This study investigated whether resistant starch types II and III are more satiating than glucose.

DESIGN AND SUBJECTS

During 4 weeks 24 healthy male volunteers consumed a daily supplement with either glucose or high-amylose corn starch (RS2) or extruded and retrograded high-amylose corn starch (RS3) in a cross-over, single-blind, randomised and balanced study design. Each type of supplement was consumed for a week. In the first week each subject consumed the glucose supplement. The RS2 and RS3 supplements provided for 30 g resistant starch/day. At the end of weeks 2, 3 and 4, subjects rated their appetite each whole hour on a visual analogue scale. Food intake was measured 1 day/week using the 24-h recall method. Subjects collected 24-h urine during the last 2 days of weeks 2, 3 and 4 to determine C-peptide excretion as a measure for the 24-h insulin secretion.

RESULTS

Supplementation with RS2 caused significantly (P < 0.05) lower appetite scores than supplementation with RS3 and glucose, though subjects paradoxically felt less full while consuming RS2. The cyclic pattern of appetite during the day did not change with the supplements. Energy and macronutrient intake was similar in the three supplementation periods. When consuming RS3, subjects had a significantly (P < 0.0012) lower urinary C-peptide excretion than when consuming RS2 or glucose: 3.74 +/- 1.42 nmol/day for RS3, 4.39 +/- 1.52 nmol/day for RS2 and 4.71 +/- 1.73 nmol/day for glucose. The mechanism for this lower insulin secretion is yet unclear.

CONCLUSION

Consumption of 30 g/day RS2 and RS3 had little influence on appetite and food intake, but RS3 reduced the insulin secretion.

Interaction between physical structure and amylose:amylopectin ratio of foods on postprandial glucose and insulin responses in healthy subjects

OBJECTIVE

To study the effect of amylose content on postprandial glucose and insulin responses in healthy subjects by serving fixed amounts of simple starchy foods with a varying but strictly controlled water, fat and guar gum content.

DESIGN

A blind, randomised, balanced cross-over study.

SETTING

The kitchen of the Nutrition Research Unit in the Unilever Research Laboratorium.

SUBJECTS

Apparently healthy employees of Unilever Research Laboratorium.

INTERVENTIONS

Subjects consumed, after an overnight fast, either a drink (12 men), a pudding (6 men and 6 women), a roll without (5 men and 6 women) or a roll with guar gum (12 men) as breakfast and the same amount of the same food as mid-morning snack. Each subject consumed the experimental food prepared in four ways: either with high- or normal-amylose starch, and with or without added fat. At 30 and 90 min after consumption of the breakfast or the snack a blood sample was taken for determination of glucose and insulin.

RESULTS

Raising the amount of amylose in starchy drinks and puddings, but not in rolls, lowered postprandial glucose and insulin responses. Fat addition to starchy drinks, puddings and rolls attenuated postprandial glucose responses, irrespective of the amount of amylose or guar gum present. Addition of guar gum to rolls reduced glucose and insulin responses. Glucose tolerance tended to be less after consumption of the experimental foods as mid-morning snack than after consumption as breakfast.

CONCLUSION

The physico-chemical composition of foods does influence the effect of the amylose:amylopectin ratio in starchy foods on postprandial glucose and insulin responses.

The effect of raw potato starch on energy expenditure and substrate oxidation

Because resistant starch (RS) is not absorbed as glucose in the small intestine of healthy humans, postprandial thermogenesis should be lower after the intake of RS as compared with digestible starch. To evaluate this hypothesis, we measured 5-h postprandial thermogenesis and substrate oxidation by indirect calorimetry after ingestion of 50 g pregelatinized (0% RS) and 50 g raw potato starch (54% type II RS) in 15 healthy, normal-weight young males. The subjects consumed each starch (mixed in diluted fruit syrup) twice on separate days and in random order. RS intake was followed by lower thermogenesis (46.5 +/- 13.1 compared with 115.4 +/- 10.4 kJ/5 h; P = 0.008), lower glucose oxidation (P < 0.0005), and greater fat oxidation (P = 0.013) than was pregelatinized starch consumption. Our results suggest that RS has no thermogenic effect and that its presence does not influence the size of the thermic response to digestible starch.

Replacement of digestible by resistant starch lowers diet-induced thermogenesis in healthy men

The present study describes the effect of replacement of digestible starch by resistant starch (RS) on diet-induced thermogenesis (DIT), postprandial glucose and insulin responses, and colonic fermentation. Ten healthy males consumed three test meals, consisting of diluted, artificially-sweetened fruit syrup and either 50 g raw potato starch (550 g RS/kg), or 50 g pregelatinized potato starch (0 g RS/kg) or 30 g pregelatinized potato starch plus 20 g lactulose (670 g indigestible disaccharide/kg). The meals were served in the morning after an overnight fast. Each volunteer consumed each meal twice on six separate days in random order. Metabolic rate was measured by indirect calorimetry in the fasting state for 15 min and postprandially for 5 h. Shortly before and hourly up to 7 h after consumption of the test meal, end-expiratory breath samples were obtained for H2 and CH4 analysis. Shortly before the meal and 30, 60, 180, and 300 min postprandially, blood samples were taken for glucose and insulin analyses. Postprandial increases in glucose and insulin levels were proportional to the amount of digestible carbohydrate in the meal. Breath H2 and CH4 concentrations indicated that the pregelatinized starch was not fermented and that lactulose was fermented rapidly. Fermentation of the raw starch started only 6 to 7 h after consumption, resulting in a rise in breath H2 but not in CH4. The replacement of 27 g digestible starch by RS in a single meal lowered DIT by on average 90 kJ/5 h, as could also be calculated by assuming that RS does not contribute to DIT. The ingestion of lactulose resulted in a substantial rise in DIT which was most probably caused by its fermentation.