| 1. |
- Lynch, Kristian, et al.
(författare)
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Context and disease when disease risk is low: the case of type 1 diabetes in Sweden
- 2010
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Ingår i: Journal of Epidemiology and Community Health. - : BMJ. - 1470-2738 .- 0143-005X. ; 64:9, s. 789-795
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Tidskriftsartikel (refereegranskat)abstract
- Background Several European studies have found significant small area variation in the risk of childhood onset (type 1) diabetes (T1D) which has been interpreted as evidence for contextual determinants of T1D. However, this conclusion may be fallacious since the limited number of newborn infants and the low risk for T1D is a source of spurious variability not properly handled by usual statistical methods. This study investigates the existence of contextual effects in the genesis of T1D, compares conclusions in previous reports with results obtained in a multilevel regression framework and highlights analysis of variance as a useful approach in public health. Methods All singletons born in Sweden between 1987 and 1991 were identified in the Medical Birth Registry (n=560 766) and followed for diabetes until age 14 using the Hospital Discharge Registry. Area variation in the cumulative incidence of T1D was estimated by different statistical methods including multilevel logistic regression. Results The risk of T1D ranged from 4.3 to 6.5 per 1000 newborns across the counties (n=24) and from 0.0 to 19.2 per 1000 newborns across the municipalities (n=284). These differences were significant in standard statistical tests (counties, p=0.02; municipalities, p=0.007). However, according to multilevel analyses, the risk of T1D ranged from 4.7 to 5.7 and from 4.4 to 6.0 per 1000 newborns in counties and municipalities, respectively, and the area variation was small and without practical relevance (counties, sigma(2)=0.006; municipalities, sigma(2)=0.017). Conclusions Previous reports based on standard statistical tests are misleading. According to multilevel analysis, administrative areas have minor relevance for individual risk of T1D in Sweden.
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| 2. |
- Lynch, Kristian, et al.
(författare)
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Cord blood islet autoantibodies and seasonal association with the type 1 diabetes high-risk genotype.
- 2008
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Ingår i: Journal of Perinatology. - : Springer Science and Business Media LLC. - 0743-8346 .- 1476-5543. ; 28:3, s. 211-217
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Tidskriftsartikel (refereegranskat)abstract
- Objective:Human leukocyte antigen DQ (HLA-DQ) genetic factors and islet autoantibodies are strongly associated with type 1 diabetes (T1D) and are currently used to predict T1D. This study examined whether islet autoantibodies in the cord blood of newborns to nondiabetic mothers were associated with the (T1D) high-risk genotype HLA-DQ2/8, gestational infections or both.Study Design:Cord blood samples were taken from 33 683 newborns and used for HLA typing and analyses of islet autoantibodies. Parents completed questionnaires when the child was 2 months of age.Result:The prevalence of newborn islet autoantibodies consistently varied with season over 4 years (P<0.0001); lowest in first quarter (1.2%) and highest in third (2.4%). Cord blood islet autoantibodies were associated with HLA-DQ2/8 in the second (OR, 2.30; P=0.02), third (OR, 2.12; P=0.008) and fourth quarters (OR, 2.49; P=0.007), but not in the first (OR, 1.13). Reported gastroenteritis was additionally associated with islet autoantibodies in the third quarter (OR, 1.80, P=0.04).Conclusion:An association between HLA and islet autoimmunity may depend on environmental exposure during pregnancy. Follow-up of mothers and children will determine risk of T1D.Journal of Perinatology (2008) 28, 211-217; doi:10.1038/sj.jp.7211912; published online 14 February 2008.
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| 3. |
- Merlo, Juan, et al.
(författare)
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Effect of neighborhood social participation on individual use of hormone replacement therapy and antihypertensive medication: a multilevel analysis.
- 2003
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Ingår i: American Journal of Epidemiology. - : Oxford University Press (OUP). - 0002-9262. ; 157:9, s. 774-783
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Tidskriftsartikel (refereegranskat)abstract
- The authors investigated a possible contextual effect of neighborhood on individual use of hormone replacement therapy (HRT) and antihypertensive medication (AHM) and the impact of neighborhood social participation on individual use of these medications. They attempted to disentangle contextual from individual influences. Multilevel logistic regression modeling was used to analyze data on 15,456 women aged 45–73 years (first level) residing in 95 neighborhoods (second level) of the city of Malmö, Sweden (250,000 inhabitants) who participated in the Malmö Diet and Cancer Study (1991–1996). AHM use was studied among 7,558 participants with defined hypertension. Of the total variability in medication use in this population, only 1.7% (HRT) and 0.5% (AHM) was between neighborhoods. After adjustment for age, individual socioeconomic factors, individual low levels of social participation, and health and behavioral variables, no neighborhood effect on AHM use was found. However, women living in neighborhoods with low social participation were much less likely to use HRT (odds ratio = 0.36, 95% confidence interval: 0.21, 0.63), especially if they themselves experienced low social participation (synergy index, 1.53) or were immigrants (synergy index, 1.68). The Malmö neighborhoods were homogeneous with regard to HRT and especially AHM use. However, differences in neighborhood social participation affected HRT use independently of individual characteristics.
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| 4. |
- Merlo, Juan, et al.
(författare)
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Individual and collective bodies: using measures of variance and association in contextual epidemiology.
- 2009
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Ingår i: Journal of Epidemiology and Community Health. - : BMJ. - 1470-2738 .- 0143-005X. ; 63, s. 1043-1048
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Social epidemiology investigates both individuals and their collectives. While the limits that define the individual bodies are very apparent, the collective body's geographical or cultural limits (e.g., "neighbourhood") are more difficult to discern. Also, epidemiologists normally investigate causation as changes in group means. However, many variables of interest in epidemiology may cause a change in the variance of the distribution of the dependent variable. In spite of that, variance is normally considered a measure of uncertainty or a nuisance rather than a source of substantive information. This reasoning is also true in many multilevel investigations, whereas understanding the distribution of variance across levels should be fundamental. This means-centric reductionism is mostly concerned with risk factors and creates a paradoxical situation, since social medicine is not only interested in increasing the (mean) health of the population, but also in understanding and decreasing inappropriate health and health care inequalities (variance). METHODS: Critical essay and literature review. RESULTS: The present essay promotes (a) the application of measures of variance and clustering to evaluate the boundaries one uses in defining collective levels of analysis (e.g., neighbourhoods), (b) the combined use of measures of variance and means-centric measures of association, and (c) the investigation of causes of health variation (variance-altering causation). CONCLUSIONS: Both measures of variance and means-centric measures of association need to be included when performing contextual analyses. The variance approach, a new aspect of contextual analysis that cannot be interpreted in means-centric terms, allows us to expand our perspectives.
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| 5. |
- Ohlsson, Henrik, et al.
(författare)
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Is the physician's adherence to prescription guidelines associated with the patient's socioeconomic position? - An analysis of statin prescription in South Sweden.
- 2010
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Ingår i: Journal of Epidemiology and Community Health. - : BMJ. - 1470-2738 .- 0143-005X. ; 64:8, s. 678-683
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Knowledge about the social and economical determinants of prescription is relevant in health care systems like the Swedish one, which is based on the principle of equity, and which aims to allocate resources on the basis of need and not on criteria that are based on social constructs. We therefore investigated the association between patient and health care practice (HCP) characteristics on the one hand, and adherence to guidelines for statin prescription on the other, with a focus on social and economic conditions. METHODS: The study included all patients in the Skåne region of Sweden who received a statin prescription between July 2005 and December 2005; 15 581 patients in 139 privately-administered HCPs and 24 593 patients in 142 publicly-administered HCPs. Socioeconomic status was established using data from LOMAS (Longitudinal Multilevel Analysis in Skåne), and stratified multilevel regression analysis was performed. RESULTS: The proportion of patients receiving recommended statins was lower among privately-administered HCPs than among publicly-administered HCPs (65% vs. 80%). Among men (but not women), low income (PRprivateHCP = 1.04 (1.01-1.09) and PRpublicHCP = 1.02 (0.99-1.07)) and cohabitation (PRprivateHCP = 1.04 (1.04-1.08) and PRpublicHCP = 1.03 (1.01-1.07)) were associated with higher adherence to guidelines. CONCLUSION: The physician's decision to prescribe a recommended statin is conditioned by the socioeconomic and demographic characteristics of the patient. Beyond individual characteristics, the contextual circumstances of the HCP were also associated with adherence to guidelines. An increased understanding of the connection between the patient's socioeconomic status and the decisions made by the physician might be of relevance when planning interventions aimed at promoting efficient and evidence-based prescription.
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| 6. |
- Wingren, Carl Johan, et al.
(författare)
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Coeliac disease in children: a social epidemiological study in Sweden
- 2012
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Ingår i: Acta Pædiatrica. - : Wiley. - 1651-2227 .- 0803-5253. ; 101:2, s. 185-191
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Little is known on the possible existence of socioeconomic and geographical differences in early coeliac disease (CD) risk. Therefore, we investigated these aspects in children before age two. Methods: Linking the Swedish Medical Birth Registry to several other national registries, we identified all singletons born in Sweden from 1987 to 1993 (n = 792 401) and followed them until 2 years of age to identify cases of CD. Applying multilevel logistic regression analysis, we investigated the association between socioeconomic position (SEP) and CD in children and also whether a possible geographical variation in CD risk was explained by individual characteristics. Results: Low SEP was associated with CD in boys OR 1.37 (95% CI 1.03-1.82), but not in girls OR 0.87 (95% CI 0.68-1.12). We found a considerable geographical variation in disease risk (i.e. intra-municipality correlation approximate to 10%) that was not explained by individual characteristics. Conclusions: Low SEP is associated with CD in boys but not in girls. Also, CD appears to be conditioned by geographical area of residence. While our study represents an innovative contribution to the epidemiology of CD in children, the reasons for the observed geographical and socioeconomic differences could be speculated but are still unknown.
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