Browsing by Subject "epidemiology"

Colorectal cancer (CRC) accounts for one in 10 new cancer cases worldwide. CRC risk is determined by a complex interplay of constitutional, behavioral, and environmental factors. Patients with ulcerative colitis (UC) are at increased risk of CRC, but effect estimates are heterogeneous, and many studies are limited by small numbers of events. Furthermore, it has been challenging to distinguish the effects of age at UC diagnosis and duration of UC. Multistate models provide a useful statistical framework for analyses of cancers and premalignant conditions. This thesis has three aims: to review the mathematical and statistical background of multistate models; to study maximum likelihood estimation in the illness-death model with piecewise constant hazards; and to apply the illness-death model to UC and CRC in a population-based cohort study in Finland in 2000–2017, considering UC as a premalignant state that may precede CRC. A likelihood function is derived for multistate models under noninformative censoring. The multistate process is considered as a multivariate counting process, and product integration is reviewed. The likelihood is constructed by partitioning the study time into subintervals and finding the limit as the number of subintervals tends to infinity. Two special cases of the illness-death model with piecewise constant hazards are studied: a simple Markov model and a non-Markov model with multiple time scales. In the latter case, the likelihood is factorized into terms proportional to Poisson likelihoods, which permits estimation with standard software for generalized linear models. The illness-death model was applied to study the relationship between UC and CRC in a population-based sample of 2.5 million individuals in Finland in 2000–2017. Dates of UC and CRC diagnoses were obtained from the Finnish Care Register for Health Care and the Finnish Cancer Registry, respectively. Individuals with prevalent CRC were excluded from the study cohort. Individuals in the study cohort were followed from January 1, 2000, to the date of first CRC diagnosis, death from other cause, emigration, or December 31, 2017, whichever came first. A total of 23,533 incident CRCs were diagnosed during 41 million person-years of follow-up. In addition to 8,630 patients with prevalent UC, there were 19,435 cases of incident UC. Of the 23,533 incident CRCs, 298 (1.3%) were diagnosed in patients with pre-existing UC. In the first year after UC diagnosis, the HR for incident CRC was 4.67 (95% CI: 3.07, 7.09) in females and 7.62 (95% CI: 5.65, 10.3) in males. In patients with UC diagnosed 1–3 or 4–9 years earlier, CRC incidence did not differ from persons without UC. When 10–19 years had passed from UC diagnosis, the HR for incident CRC was 1.63 (95% CI: 1.19, 2.24) in females and 1.29 (95% CI: 0.96, 1.75) in males, and after 20 years, the HR was 1.61 (95% CI: 1.13, 2.31) in females and 1.74 (95% CI: 1.31, 2.31) in males. Early-onset UC (age <40 years) was associated with a markedly increased long-term risk of CRC. The HR for CRC in early-onset UC was 4.13 (95% CI: 2.28, 7.47) between 4–9 years from UC diagnosis, 4.88 (95% CI: 3.46, 6.88) between 10–19 years, and 2.63 (95% CI: 2.01, 3.43) after 20 years. In this large population-based cohort study, we estimated CRC risk in persons with and without UC in Finland in 2000–2017, considering both the duration of UC and age at UC diagnosis. Patients with early-onset UC are at increased risk of CRC, but the risk is likely to depend on disease duration, extent of disease, attained age, and other risk factors. Increased CRC risk in the first year after UC diagnosis may be in part due to detection bias, whereas chronic inflammation may underlie the long-term excess risk of CRC in patients with UC.

BACKGROUND: Diet has a major influence on the human gut microbiome, which has been linked to health and disease. However, epidemiological studies on the association of a healthy diet with the gut microbiome utilizing a whole-diet approach are still scant. OBJECTIVES: To assess associations between healthy food choices and human gut microbiome composition, and to determine the strength of association with the functional potential of the microbiome. DESIGN: The study sample consisted of 4,930 participants in the FINRISK 2002 study. Food intake was assessed using a food propensity questionnaire. Intake of food items recommended to be part of a healthy diet in the Nordic Nutrition Recommendations were transformed into a healthy food choices (HFC) score. Microbial diversity (alpha diversity) and compositional differences (beta diversity) and their associations with the HFC score and its components were assessed using linear regression and permutational multivariate analysis of variance (PERMANOVA). Associations between specific taxa and HFC were analyzed using multivariate associations with linear models (MaAsLin). Functional associations were derived from KEGG orthologies (KO) with linear regression models. RESULTS: Both microbial alpha (p = 1.90x10-4) and beta diversity (p ≤ 0.001) associated with HFC score. For alpha diversity, the strongest associations were observed for fiber-rich breads, poultry, fruits, and low-fat cheeses. For beta diversity, most prominent associations were observed for vegetables followed by berries and fruits. Genera with fiber-degrading and short-chain fatty acids (SCFA) producing capacity were positively associated with the HFC score. HFC associated positively with KO-based functions such as vitamin biosynthesis and SCFA metabolism, and inversely with fatty acid biosynthesis and the sulfur relay system. CONCLUSIONS: These results from a large and representative population-based survey confirm and extend findings of other smaller-scale studies that plant and fiber-rich dietary choices are associated with a more diverse and compositionally distinct microbiome, and with a greater potential to produce SCFAs.

Tausta Olkavarren murtumat ovat vammoina verrattain yleisiä ja niitä luokitellaan murtuman sijainnin sekä murtuman morfologian mukaan. Epidemiologiset katsaukset auttavat ymmärtämään vammojen taustalla olevia tekijöitä sekä luovat perustaa tulevaisuuden tutkimustyölle. Toistaiseksi laajoja olkavarren murtumiin kohdistuvia epidemiologisia tutkimuksia on julkaistu vain muutamia. Aineisto ja menetelmät Analysoimme retrospektiivisesti vuosina 2006–2016 Töölön sairaalassa hoidossa olleiden olkavarren murtuman saaneiden aikuispotilaiden sairauskertomukset. Me keräsimme potilastietojärjestelmistä potilaita koskevia taustatietoja ja murtumaan liittyen vammamekanismin ja -ajan, liitännäisvammat sekä laskimme kuolleisuuden vuoden kuluessa vammasta. Löydökset 11 vuoden aikana Töölön sairaalassa hoidettiin 914 potilasta (489 naispotilasta, mediaani-ikä 61,4 vuotta; 425 miespotilasta, mediaani-ikä 50,4 vuotta), joilla oli yhteensä 936 olkavarren murtumaa. Yli 60 % näistä murtumista johtui kaatumisesta samalla tasolla. Potilaiden ikäjakauma oli kaksihuippuinen: eniten murtumia esiintyi iäkkäissä naisissa sekä nuorissa miehissä. Jaoimme olkavarren murtumat 1) tyypillisiin traumaattisiin murtumiin, 2) periproteettisiin sekä 3) patologisiin murtumiin. 872:sta tyypillisestä murtumasta 3,0 % oli avoimia murtumia. Periproteettisia murtumia oli 24 (2,6 %) ja patologisia murtumia 40 (4,3 %). 24 %:lla murtumapotilaista oli liitännäisvammoja, joista yleisin oli primaarinen radiaalihermon halvaus (10 %). Primaarinen radiaalihermon halvaus oli yleisempää distaalisen olkavarren murtumissa sekä korkeaenergisissä vammoissa verrattuna muihin murtumiin. Murtuman jälkeinen ensimmäisen vuoden kuolleisuus oli 9,2 %. Pohdinta Tutkimuksemme mukaan olkavarren murtuma johtuu useimmin kaatumisesta samalla tasolla. Yleisin liitännäisvamma oli primaarinen radiaalihermon halvaus. Toteamamme olkavarren murtumien kaksihuippuinen ikäjakauma on yhdenmukainen aiemman kirjallisuuden kanssa.

Tavoitteet: Itä-Euroopassa ja Keski-Aasiassa HIV-1-infektioiden ilmaantuvuus on noussut 57 % vuosina 2000−2015. Epidemiologista dataa on edelleenkin vähän. Lisäksi se on pääosin venäjänkielistä, eikä ole saatavilla kansainvälisten tietokantojen kautta. Suunnitelma: Keräsimme näytteitä ja epidemiologista dataa 328 HIV-tartunnan saaneelta, joista 91 % asui Venäjän Eteläisen federaatiopiirin alueella ja 9 % Pohjois-Kaukasian federaatiopiirin alueella. Menetelmät: Proteaasi-käänteiskopioijaentsyymi- (PRRT) ja integraasisekvessejä (IN) käytettiin viruksen alatyypin selvittämiseen sekä resistenssimutaatioiden ja lääkeherkkyyksien analysointiin. Fylogeneettisiä analyysejä käytettiin HIV:n ala-alatyyppien A6 ja A1 erottamiseen toisistaan. Tulokset: 303 (92 %) potilaan näytteet pystyttiin analysoimaan, näistä 32 %:lla infektio oli saatu huumeiden pistoskäytön kautta, 27 %:lla heteroseksissä ja 24 % infektioista oli nosokomiaalisia eli hoidon seurauksena tulleita. Miehillä huumeiden pistoskäyttö oli yleisin syy infektioille, naisilla heteroseksi. Tutkimuksessa todettiin eniten A6-viruksia (69 %), joita esiintyi erityisesti huumeita pistämällä käyttävillä sekä heteroseksin kautta saaduissa tartunnoissa. Tätä ja tulevia tutkimuksia varten luotiin A6-pol-referenssisekvenssi. Alatyypin B infektioita esiintyi erityisesti miehillä, joilla oli ollut miesten välistä seksiä. Alatyypin G infektiot olivat yhteydessä nosokomiaaliseen infektioon. Lääkeresistenssimutaatioita havaittiin PI-, NRTI-, NNRTI- ja INI-lääkeaineryhmiä kohtaan. Spesifisten mutaatioiden esiintyvyys korreloi tiettyjen HIV:n alatyyppien kanssa. Esimerkiksi ala-alatyyppi A6 yhteydessä esiintyi merkittävästi enemmän mutaatioita NRTI A62V sekä NNRTI G190S, kun taas alatyyppiin G korreloivat NRTI-lääkeaineryhmään liittyvät mutaatiot D67N ja M41L. Näytteissä havaittiin lääkeherkkyyden alentuma: 14,5 % PI-, 29,6 % NNRTI-, 27,1 % NNRTI- ja 8,2 % INI-ryhmän lääkkeitä kohtaan. Yhteenveto: Tutkimuksessa havaittu HIV-1 alatyyppijakauma Venäjällä on merkittävästi erilainen kuin Saksassa. A6 oli yleisin tutkimuksen näytteissä havaittu alatyyppi samoin kuin muissakin Venäjälle sijoittuvissa tutkimuksissa on kuvattu. Alatyyppiä G esiintyi poikkeuksellisen paljon tämän tutkimuksen näytteissä verrattuna muihin Venäjältä julkaistuihin tutkimuksiin, mikä viittaa paikalliseen epidemiaan. HIV-1:n resistenssitestauksen yleistyminen parantaisi HIV-lääkehoidon tehokkuutta sekä toisi lisätietoa Venäjän HIV-epidemiasta. (271 sanaa)

Finnish conscripts have proven to be an excellent study group for epidemiological research within oral health in the past decades. The aim of this cross-sectional study was to determine the geographical distribution of dental caries prevalence in young healthy males in Finland in the beginning of the 2020s. Studying associated risk factors for dental caries were of interest as well. The data were randomly collected from the eight biggest garrisons in Finland in July of 2021 by ten calibrated dentists. The study population consisted of 2077 male conscripts born between 2000-2002. Dental caries was recorded according to the ICDAS system. Wisdom teeth were excluded. Mean DMFT and mean DT values were calculated and geomaps were constructed to visualize the geographical distribution. Generalized linear mixed models with logit link were conducted for the associated risk factors. The mean DMFT value of all conscripts was 3.29 (SD 3.91), while the mean DT value was 1.19 (SD 2.33). Living in areas with endemic fluoride levels in drinking water ≥0.3 mg/l, decreased the odds for restorative treatment need. The geographical distribution of dental caries prevalence remains like before. However, the overall restorative treatment need and treatment history has decreased countrywide.

Background: Asthma with NSAID-exacerbated respiratory disease (NERD) is associated with uncontrolled or severe asthma. NERD patients are more prone to severe allergic reactions and their asthma exacerbations lead to hospitalisations twice as often compared to patients with non-NERD-asthma. NERD patients are prone to recurrent nasal polyposis requiring frequent endoscopic sinus surgeries. However, the early risk factors of NERD are not fully understood. The aim was to identify risk factors of NERD among patients with adult-onset asthma. Methods: We used data from 1350 population-based adult asthmatics with adult-onset asthma from Finnish national registers. NERD was defined as self-reported wheeze or other typical respiratory symptoms after ingestion of NSAIDs. Thirty-six covariates covering several domains (personal characteristics, life-style, early life factors, asthma characteristics and multimorbidities) were selected based on literature and were studied in association with NERD using logistic regressions. Results: The study population included 153 (11.3%) asthmatics with NERD. Thirty-six covariates were entered in univariate logistic regression analysis, in which 23 were associated with NERD (p < 0.05). These variables were entered in a multivariable logistic regression model in which allergic respiratory symptoms, female sex, osteoarthritis, difficult asthma, nasal polyps, second-hand smoke exposure at home, having 3 or more older siblings and being overweight were significantly associated with asthma with NERD (p < 0.05). Overweight decreased the risk of NERD, other factors increased it. Conclusion: According to our study, risk factors of NERD in part are associated with female sex, BMI, exposure to tobacco smoke, allergy, orthopaedic disorders and infection history, and their early recognition might thus be important to manage the burden of NERD.

Introduction: Working conditions have not only been found to impact work ability and productivity, but the overall health of employees. The working environment is a relevant health factor for a considerable part of the population. In research, work-related mental strain has been associated with body weight change, yet no causal relationship can be confirmed based on the existing evidence. Of the psychosocial factors, low job control, as well as both high and low job demands have been associated with weight gain. Most of the research so far has been done with cross-sectional data; long-term follow-ups are scarce and only little research has been done on the association between changing working conditions and body weight change. Aim: The general aim of this study was to examine the association between changes in psychosocial working conditions and body weight change among midlife women and men. The association between two psychosocial work characteristics, job demands and job control, and weight gain during the follow-up was examined in a cohort study among the employees of the City of Helsinki in Finland. The main research question was: (i) Is change in job demands and job control associated with major weight gain during a 10- to 12-year follow-up period among midlife employees? In addition, the contribution of several background and lifestyle factors were taken into account. Especially the contribution of baseline BMI-status, dietary habits and leisure-time physical activity to the association between psychosocial working conditions and major weight gain was studied. Methods: The data were collected from a mail survey among the employees of the City of Helsinki in 2000–2002, 2007 and 2012. The study sample consisted of employees who were 40, 45, 50, 55 and 60 years old at the beginning of the survey in 2000–2002. Exclusion criterions were BMI <18.5kg/m2 in phase 1, retiring before phase 2, and drop out before phase 3. Hence, the final study sample (n=4,630) consisted 52% of the original study population, of which 83% were women. Psychosocial working conditions were assessed with a validated Job Content Questionnaire (JCQ) by Karasek and Theorell in phase 1 and 2. Weight change was assessed between phases 1 and 3, and major weight gain was defined as at least 10% weight gain during that time period. Dietary habits were assessed using a 20-item Food Frequency questionnaire (FFQ). Based on the current national dietary recommendations, nine food habits were chosen and their usage frequency was used as a determinant of healthy food habits. Leisure time physical activity was assessed with metabolic equivalent tasks (METs). Logistic regression analysis was used to examine the associations between changing job demands, job control, and major weight gain. All the analyses were stratified by gender. In addition, further stratification was made by the baseline BMI. Results: Weight gain was common among the study population. Major weight gain was observed among 27% of women and 15% of men. A weak association between change in job demands and major weight gain was found among both genders. Among women, the risk of major weight gain was higher among those who reported persistent high job demands (OR 1.22 95% CI 1.02–1.48 full adjusted model) compared with those with persistent low job demands. Among men, in contrast, the risk was higher among those who reported decreased job demands compared with those who reported persistent low job demands (OR 1.80 95% CI 1.02–3.16 full adjusted model). When further stratified by the BMI in phase 1, the risk was higher only among overweight or obese women, whereas among men the increase in risk was seen among both normal weight and overweight or obese participants. Dietary habits and leisure time physical activity did not affect the association of changing psychosocial working conditions with major weight gain. However, they had a minor own effect on the risk. Change in job control was not associated with the risk of major weight gain. Conclusions: The study shows that change in job demands is weakly associated with major weight gain. Future research is needed especially among other employers than municipalities, and especially among men. Changing working conditions should be studied with shorter follow-up periods, while taking into account also the role of social support at the workplace.