The risk of occupational rhinitis

 Objective Reports on the aetiology and risk of occupational rhinitis in different occupations are scarce. Method: The purpose of this study was to find the occupations with an increased risk of occupational rhinitis. Age and gender differences in occupational rhinitis and occupational asthma were also compared, and the most common causes of occupational rhinitis were analysed. Design: This study covered the cases of occupational rhinitis and asthma reported to the Finnish Register of Occupational Diseases during the years 1986–1991. The cases on the Register were linked to the longitudinal census data file from the Finnish censuses. Results: During 1986–1991, 1244 new cases of occupational rhinitis (747 women and 497 men) and 1867 new cases of occupational asthma (916 women and 951 men) were reported to the Register. Animal dander, flours, wood dusts, textiles, phthalic acid anhydrides and storage mites were important causes of occupational rhinitis. The highest relative risk of occupational rhinitis was among furriers, the age-standardized rate ratio (SRR) was 30.0. Bakers and livestock breeders had also a markedly elevated relative risk (SRR=22.0). Men had the highest incidence of occupational rhinitis at the age of 25–29 years and among women the incidence gradually increased and reached the peak in the group 40–44 years of age. Conclusion: Furriers, bakers, and livestock breeders had the most elevated relative risk of occupational rhinitis. Occupational rhinitis cases appeared at a younger age than asthma, suggesting that rhinitis often precedes asthma. Received: 26 June 1996/Accepted: 16 October 1996     

Serum beta-N-acetylglucosaminidase and beta-glucuronidase activities in silicosis patients and in workers exposed to silica dust

The serum activities of two lysosomal enzymes, beta-N-acetylglucosaminidase (EC 3.2.1.30; NAG) and beta-glucuronidase (EC 3.2.1.31; GLU) were analysed in 116 male patients with silicosis. Twenty-eight of the patients were matched with controls of similar sex, age and exposure to silica dust but with no radiographical evidence of silicosis. A control group which had not been exposed to silica dust consisted of male blood donors. The mean activity of NAG in serum was higher in the silicosis patients than in the blood donors (P less than 0.01). Similarly, the NAG level in the silicosis patients with matched controls was higher than that in the silica-exposed controls (P less than 0.05). The silicosis patients who showed a progression of small opacities by one or more subcategories had a slightly higher mean NAG activity in their sera than the patients with no progression but this difference did not reach statistical significance; the activity was higher than in silica-exposed controls (P less than 0.05). We suggest that these findings may be related to the effects of silica on macrophages which have been observed experimentally in vitro and in vivo and might indicate an increased turnover of macrophages caused by silica dust and active, progressive silicotic fibrosis.     

Effect of dietary fat on blood pressure in a rural Finnish population

Thirty couples living in Liperi, a community of North Karelia, aged 40 to 50 yr participated in a dietary intervention study to assess the influence of dietary fat on blood pressure and other parameters. After a weeklong base-line period the subjects consumed a low fat diet (24% of energy) with a polyunsaturated/saturated fat ratio (P/S) of 1.2 for 6 wk. After this 6-wk intervention period the subjects resumed their normal diets (36% energy from fat, P/S 0.15) for an additional 6-wk period. Body weight remained constant throughout the study and salt intakes were approximately 12 g/day. During the low fat, high P/S period a decrease of 7.5 and 2.8 mm Hg pressure occurred for systolic and diastolic blood pressure from the base-line level. When the normal diet was resumed, systolic and diastolic blood pressures increased by 7.7 and 6.3 mm Hg, respectively, from the levels observed at the end of the intervention period.     

Bioavailability of selenium in mushrooms, Boletus edulis, to young women

The bioavailability of selenium (Se) in mushrooms, Boletus edulis, to young Finnish women was studied by giving them 150 micrograms Se as mushrooms for 4 weeks. The indicators of body selenium status were plasma and erythrocyte Se levels and plasma and platelet glutathione peroxidase (GSH-Px) activity. The Se level in erythrocytes increased significantly (26%), while only slight enhancement were found in plasma Se and plasma or platelet GSH-Px activity. The results indicate that the metabolism of mushroom-Se is different from that of wheat-Se or sodium selenate. However, by the criteria of plasma Se level or plasma and platelet GSH-Px activity the bioavailability of mushroom-Se is reasonably low.     

Congenital malformations by the parental occupation in finland

Summary The Finnish Register of Congenital Malformations, a case-referent register, was used to analyze the associations between the parental occupation and the children born with malformations. The women working in industrial and construction occupations had more children with central nervous system (CNS) and musculoskeletal malformations than the referent mothers. The women employed in transport and communication occupations had more children with oral clefts as compared to the referent mothers. The specific occupations with an increased odds ratio included telephone operators and teachers (oral clefts), and gardeners and women in food industry and unspecific factory work (musculoskeletal malformations). No statistically significant odds ratios were found when the material was analysed according to the paternal occupation. Some associations were found with a low social class and malformations.     

Effects of a flaxseed mixture and plant oils rich in alpha-linolenic acid on the adenoma formation in multiple intestinal neoplasia (Min) mice

Flaxseed is a dietary source of possible chemopreventive compounds such as lignans and alpha-linolenic acid (ALA). To study the effects of a flaxseed mixture on adenoma formation in multiple intestinal neoplasia mice, the mice were fed a diet containing 2.7 % flaxseed, 4.5 % fibre and 3.7 % ALA. To elucidate the effect of oils of the mixture we also composed a diet without flaxseed but with the same oil composition. The median number of adenomas in the small intestine was fifty-four for the control group, and thirty-seven (P=0.023) and forty-two (P=0.095) for flaxseed and oil groups, respectively. Compared with controls (1.2 mm), the adenoma size was smaller in the flaxseed (0.9 mm; P=0.002) and oil (1.0 mm; P=0.012) groups. Both diets changed the proportions of n-3 and n-6 fatty acids in the colonic mucosa. Membrane beta-catenin and protein kinase C (PKC)-zeta levels were reduced in the adenoma v. mucosa (P<0.05), and an inverse association was found between the membrane PKC-zeta in the mucosa and the adenoma number (r -0.460, P=0.008, n 32). Only the flaxseed diet increased lignan levels in the caecum (P=0.002) and in plasma (P=0.002) but they were not associated with tumour formation. The results suggest that the preventive effect of flaxseed on colon carcinogenesis may be due to the oil part of flaxseed, and the loss of beta-catenin and PKC-zeta from the membranes of the mucosal tissue may play a permissive role in intestinal tumour development.     

PASSCLAIM - Diet-related cardiovascular disease

Cardiovascular disease (CVD) has a multifactorial aetiology and many potential risk markers are known. As it was not feasible to discuss all markers and their possible interactions in relation to all aspects of CVD, selections had to be made in this paper. In the context of claims and functional foods, emphasis was placed on those aetiological processes and risk markers that have been shown previously to be modified by diet: lipid and lipoprotein metabolism, haemostatic function, oxidative damage, homocysteine metabolism, and blood pressure. Except for methodological and biological characteristics of these biomarkers, their relationships with the risk of CVD are discussed. For LDL and HDL cholesterol, fasting triacylglycerol, homocysteine, and blood pressure well-validated, easy applicable, and generally accepted biomarkers exist. For haemostatic function and oxidative damage validation of markers with respect to CVD or intermediate clinical markers is recommended. For diet-related CVD, however, the ultimate question is whether changes in the biomarker are truly related to changes in risk. Only for LDL cholesterol and blood pressure does consensus exist among scientists for a possible application as enhanced function claims. For HDL, triacylglycerol, and homocysteine, and in particular for haemostatic function and oxidative damage, however, formal proof is lacking that diet-induced changes in these biomarkers alter the risk of CVD. At the same time, it should be emphasised that CVD is multifactorial. Therefore it does not seem justified that a change in one particular biomarker is enough evidence to substantiate a claim. There are examples of food components or drugs that one biomarker is changed in a favourable way, but at the same time another biomarker is changed in an unfavourable way. Therefore, studies to further validate generic predictors for the CVD risk should be initiated.     

Suitability of a batch in vitro fermentation model using human faecal microbiota for prediction of conversion of flaxseed lignans to enterolactone with reference to an in vivo rat model

Summary Background In vitro fermentation models have been used widely for studies of shortchain fatty acid (SCFA) formation from carbohydrates, whereas the suitability of these methods for enterolactone (ENL) formation has received less attention. Aim The aim was to study the suitability of an in vitro fermentation model for prediction of bioconversion of lignans to ENL, to compare the approach with that of an in vivo rat model and to study the SCFA formation in both models. Methods Predigested samples of rye bran (R), flaxseed meal (F) alone, or in combination with rye bran (R&F) and a faecal control were incubated in an in vitro fermentation model using human faecal microbiota. In the in vivo experiment rats consumed a non–fibre control diet (C) or diets supplemented either with rye bran (R), flaxseed meal (F) alone, or with their combination (R&F) for four weeks. Enterodiol (END), ENL and SCFA concentrations were measured from in vitro faecal fermentation samples and from the intestinal contents of rats. Plasma ENL concentrations from rats were also measured. Results The highest ENL production was found in vitro with the F supplement (areas under curve: 740 ± 4, 7500 ± 400, 2600 ± 500 and 1520 ± 70 nmol · h for the R, F, R&F supplements and faecal control, respectively). In vivo, the concentration of ENL in caecal digesta from flaxseed meal was significantly (P < 0.05) enhanced by the presence of rye bran (medians 261, 407 and 24 nmol/g in the F, R&F and C groups, respectively). No correlation was found between the models regarding ENL production, possibly due to different responses to the presence of rye bran matrix, differences in microbiota or application of a batch in the in vitro fermentation model. Rye bran supplementation enhanced butyrate production both in vitro and in vivo. Conclusion In vitro fermentation and the in vivo rat models responded differently to the presence of rye bran and no correlation with regard to the ENL formation from flaxseed lignans was observed.     

Ellagic acid and natural sources of ellagitannins as possible chemopreventive agents against intestinal tumorigenesis in the Min mouse

Ellagic acid has been shown to have chemopreventive effects in various experimental cancer models. We wanted to see whether pure ellagic acid and natural ellagitannins from cloudberry (Rubus chamaemorus) seed and pulp have any effect on adenoma formation in Apc-mutated Min mice. From the age of 5 wk, the mice were fed either a control diet, a diet containing pure ellagic acid at 1,564 mg/kg, or diets containing 4.7% (wt/wt) cloudberry seeds or 5.3% cloudberry pulp. The concentrations of ellagitannins and free ellagic acid in the seed diet were 807 and 42 mg/kg and in the pulp diet 820 and 34 mg/kg, respectively. After the 10-wk feeding period, ellagic acid had no effect on the number or size of adenomas in the distal or total small intestine, but it increased adenoma size in the duodenum when compared with the control diet (1.50+/-0.29 vs. 1.16+/-0.31 mm; P=0.029). Neither cloudberry seed nor pulp diets had any effect on the adenoma formation. Chemopreventive effects and mechanisms of whole cloudberry and other similar sources of phenolic compounds should, however, be studied, further taking into account food matrix and interactions with other dietary constituents that may be involved in the bioavailability and metabolism of ellagitannins.     

Relative nutritional availability to rats of selenium in Finnish spring wheat (Triticum aestivum L.) fertilized or sprayed with sodium selenate and in an American winter bread wheat naturally high in Se

A Finnish national programme to fertilize crops with sodium selenate led us to compare the nutritional availability to rats of selenium in two Finnish spring wheats (Triticum aestivum L.), either fertilized or sprayed with sodium selenate, with that in an American winter bread wheat naturally high in Se. Weanling male rats were given a Se-deficient Torula yeast diet for 4 weeks followed by either continued depletion or repletion for 4 weeks with graded levels of Se as sodium selenite (standard) or wheat (test food). Plasma and liver Se levels and plasma and liver glutathione peroxidase (EC 1.11.1.9; GSH-Px) activities were used as criteria of body Se status. The availability of Se under these conditions was calculated with the point-slope technique at two dietary levels of Se (Expt 1) and with the slope-ratio method (Expt 2). In the point-slope assay, the level of dietary Se fed had a considerable effect on the apparent availability values obtained which made interpretation of the results difficult. In the slope-ratio assay, no difference in the availability of Se from the various wheats was observed when plasma or liver Se levels were used as the response criteria. The Se in the fertilized wheat was somewhat more available than that in the sprayed wheat when plasma or liver GSH-Px activities were the response criteria. Overall, availability values (%) derived by averaging all four response criteria were 86, 77 and 73 for the fertilized and sprayed Finnish wheats and the American wheat respectively (sodium selenite 100). These results show that wheat is a relatively available source of Se to rats regardless of whether its Se content is naturally high or is increased by fertilization or spraying.