Niklas Hammar

Karolinska Institutet, Сольна, Stockholm, Sweden

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Publications (179)838.2 Total impact

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    ABSTRACT: Background: Patients with diabetes mellitus have a lower incidence of prostate cancer. It has been hypothesised that this reduction is due to hypoinsulinemia which may play a role in counteracting the potential carcinogenic effects of hyperglycaemia, androgens and Insulin Growth Factor-1 bioactivity. In this prospective study, we aimed to investigate the association between pre-diagnostic serum glucose and prostate cancer grade among Swedish men with prostate cancer. Methods: The study comprised 14768 Swedish men who were diagnosed with prostate cancer between 1996 and 2011. We extracted information on age at diagnosis, educational level, fasting status, serum lipids and serum glucose from the Swedish AMORIS database. Information on Gleason score was retrieved through linkage with the National Prostate Cancer Registry. Our primary outcome was prostate cancer severity which was characterised by low grade (N=7275), intermediate (N=5045) or high grade (N=2448) prostate cancer. Univariate and multivariate logistic regression was used to investigate the association between serum glucose levels (clinical cut-off points) and prostate cancer severity. We also conducted further stratified analyses to assess the differences in association among men <60, 60-69 and ≥60 years. Results: Mean age was 67 years. Hyperglycaemia was positively associated with intermediate (Gleason 7) and high grade (Gleason 8+) prostate cancer (adjusted odds ratio (OR) for ≥ 5.6mmol/l versus < 5.6mmol/l: 1.17; 95 %CI: 1.04-1.30 and 1.25; 1.09-1.44 respectively). In men aged 60-69 years, hyperglycaemia was positively associated with risk of intermediate and high grade prostate cancer (adjusted odds ratio (OR) for ≥ 5.6mmol/l vs < 5.6mmol/l: 1.25; 1.07-1.47 and 1.53; 1.23-1.89, respectively), compared to low or normal serum glucose levels. Conclusion: Our findings suggest that higher serum glucose may influence prostate cancer aggressiveness.
    NCRI Cancer Conference, Liverpool, England; 11/2015
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    ABSTRACT: Background: In a cohort study using the Swedish Apolipoprotein-related MOrtality RISk (AMORIS) study, we investigated the associations between selected serum metabolic markers, which are potentially linked to carcinogenic processes such as oxidative stress and inflammation, and prostate cancer severity at time of diagnosis. Materials and Methods: The study comprised 13,273 Swedish men who were diagnosed with prostate cancer between 1996 and 2011. We extracted information on age at diagnosis, educational level, Charlson co-morbidity index and serum total cholesterol, triglycerides and glucose from the Swedish AMORIS study. Information on clinical characteristics including TNM stage, Gleason score and PSA values was also retrieved through linkage with the National Prostate Cancer Registry. Our primary outcome was prostate cancer severity categorised as low (N=4,463), intermediate (N=4,212) and high (N=3,460) risk localised prostate cancer and regional/distant metastatic (N=2,333) disease. Univariate and multivariate logistic regression was used to investigate the relation between glucose, triglycerides and total cholesterol and prostate cancer severity. Stratified analyses by age were also conducted. In sensitivity analyses, we excluded men with measurements taken less than 1.5 years prior to prostate cancer diagnosis to assess reverse causation. Results: Mean age at time of prostate cancer diagnosis was 67 years. Hyperglycaemia was associated with increased risk of high risk localised prostate cancer and regional/distant metastatic prostate cancer (adjusted odds ratio (OR) for ≥ 5.6mmol/l vs < 5.6mmol/l: 1.23; 95 %CI: 1.08-1.40 and 1.34; 1.14-1.57 respectively). Triglycerides also had a statistically significant positive association with high risk localised prostate cancer (adjusted OR for ≥ 1.7mmol/l vs < 1.7mmol/l: 1.13; 95% CI 1.01-1.26), but not regional/distant metastatic prostate cancer (1.08; 0.95-1.23). No statistically significant association was observed between total cholesterol and high risk localised prostate cancer or regional/distant metastatic prostate cancer. None of the serum markers were associated with intermediate risk localised prostate cancer. Furthermore, there were no differences in the relation between any of the serum markers and prostate cancer severity among age groups. Similar findings were obtained after excluding men with measurements taken less than 1.5 years prior to prostate cancer diagnosis. Conclusion: Our findings suggest that high serum glucose and triglycerides may increase risk of severe prostate cancer.
    European Cancer Congress, Vienna, Austria; 09/2015
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  • H Malmström · G Walldius · V Grill · I Jungner · N Hammar
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    ABSTRACT: Glycation is linked to microvascular complications of diabetes and also to macrovascular events. Fructosamine is a biomarker of glycation but its associations to macrovascular complications are not well documented. The aim of this study was to evaluate fructosamine as a predictor of myocardial infarction and all-cause mortality in a large population based cohort. Information on glucose and fructosamine was obtained from subjects of the AMORIS cohort (n = 338,443) followed for 19 years on average. Incident cases of myocardial infarction and death from any cause were identified from national patient and cause of death register respectively. The incidence of myocardial infarction (n = 21,526 cases) and all-cause mortality (n = 73,458 deaths) increased at a fructosamine of 2.30 mmol/L or above. For myocardial infarction, the sex-age- fasting- and entry period adjusted hazard ratio in subjects above 2.70 mmol/L vs. reference range subjects was 2.88 (95% CI: 2.70-3.07). The corresponding hazard ratio for all-cause mortality was 2.31 (95% CI: 2.21-2.41). These associations remained basically unchanged after adjustment for total cholesterol, triglycerides, albumin, social class, smoking and hypertension. When additional adjustment for glucose was performed the associations were attenuated but remained. In a sub cohort with simultaneous measurements of fructosamine, HbA1c and fasting glucose respectively similar associations were observed (n = 9746). There is a strong association between fructosamine and myocardial infarction and death from any cause when major cardiovascular risk factors are accounted for. In addition, this association could only partly be explained by glucose levels. Copyright © 2015 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.
    Nutrition, metabolism, and cardiovascular diseases: NMCD 07/2015; DOI:10.1016/j.numecd.2015.07.002 · 3.88 Impact Factor
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    Atherosclerosis 07/2015; 241(1):e135. DOI:10.1016/j.atherosclerosis.2015.04.466 · 3.99 Impact Factor
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    ABSTRACT: Inflammation has been linked to cancer but its role in breast cancer is unclear. We investigated common serum markers of inflammation: C-reactive protein (CRP), albumin, haptoglobin, and white blood cells (WBC) in relation to breast cancer incidence, severity and survival. A total of 155,179 women aged 20 and older without any history of cancer were selected from a large Swedish cohort. Hazard ratios (HRs) for breast cancer were estimated with Cox regression, adjusting for potential confounders. Ordered and binomial logistic regression models were used to assess the associations of serum inflammatory markers with breast cancer severity and ER positivity at diagnosis, on the other. Cumulative incidence functions by levels of inflammatory markers were assessed for early death from breast cancer and all causes. During a mean follow-up of 18.3 years, 6,606 women were diagnosed with breast cancer, of whom 1,474 died. A positive association with incident breast cancer was seen for haptoglobin ≥ 1.4 g/L (HR 1.09; 95% confidence interval [CI]: 1.00-1.18) compared to lower levels. No association was observed between inflammatory markers and breast cancer severity or ER positivity. Higher haptoglobin was linked to risk of early death from breast cancer (HR: 1.27, 95% CI: 1.02-1.59), whereas higher risk of early death from all causes was additionally found with CRP ≥ 10 mg/L (HR: 1.19, 95% CI: 1.04-1.36) and WBC ≥ 10 x 10(9)/L (HR: 1.57, 1.14-2.16). Our findings indicate that prediagnostic serum inflammatory markers were weakly linked to incident breast cancer but corresponded to worse survival after diagnosis. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Carcinogenesis 06/2015; DOI:10.1093/carcin/bgv096 · 5.27 Impact Factor
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    ABSTRACT: Background Although coronary revascularization by coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) is well documented, scientific knowledge on disability pension (DP) at time of revascularization is sparse. The aim was to investigate the prevalence of all-cause and diagnosis-specific DP at time of a first coronary revascularization, accounting for sociodemographic and medical factors. Methods A population-based, cross-sectional study, using Swedish registers, was conducted including all 65,676 patients (80% men) who, when aged 30-63 years, within 1994-2006, had a first CABG (n = 22,959) or PCI (n = 42,717) and did not have 314
    PLoS ONE 11/2014; 10(1): e0115540.. DOI:10.1371/journal.pone.0115540 · 3.23 Impact Factor
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    ABSTRACT: Background Although coronary revascularization by coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) is well documented, scientific knowledge on disability pension (DP) at time of revascularization is sparse. The aim was to investigate the prevalence of all-cause and diagnosis-specific DP at time of a first coronary revascularization, accounting for sociodemographic and medical factors. Methods A population-based, cross-sectional study, using Swedish registers, was conducted including all 65,676 patients (80% men) who, when aged 30-63 years, within 1994-2006, had a first CABG (n = 22,959) or PCI (n = 42,717) and did not have 314
    7th European Public Health Conference, Glasgow, United Kingdom; 11/2014
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    ABSTRACT: Context Fructosamine is a glycemic biomarker which may be useful for indication and control of diabetes respectively. Objective The objective of the study was to evaluate fructosamine as an indicator of hyperglycaemia and glucose control in subjects with diabetes. Design, Setting & Patients From the AMORIS cohort, subjects with serum glucose, fructosamine and HbA1c from the same examination were studied cross-sectionally and longitudinally (n = 10,987; 5,590 overnight-fasting). The guidelines of the American Diabetes Association were followed for classification of prediabetes and diabetes. Separate analyses were performed in patients with a newly detected or a known diagnosis of type 1 or type 2 diabetes respectively. Results All three biomarkers were strongly correlated. With regard to the association between fructosamine and HbA1c Pearson linear correlation coefficients in the range of 0.67–0.75 were observed in fasting and non-fasting subjects with type 1 or type 2 diabetes. Analyses of glucose control in fasting patients with type 2 diabetes having all three biomarkers measured at three separate occasions within on average 290 days of the index examination showed similar trends over time for glucose, fructosamine and HbA1c. Discrimination of subjects with and without diabetes across the range of fructosamine levels was good (area under curve (AUC) 0.91–0.95) and a fructosamine level of 2.5 mmol/L classified subjects to diabetes with a sensitivity of 61% and a specificity of 97%. Conclusions Fructosamine is closely associated with HbA1c and glucose respectively and may be a useful biomarker of hyperglycaemia and glucose control in clinical and epidemiological studies.
    PLoS ONE 10/2014; 9(10):e111463. DOI:10.1371/journal.pone.0111463 · 3.23 Impact Factor
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    ABSTRACT: Acute kidney injury (AKI) after coronary artery bypass grafting (CABG) is associated with early mortality. Its impact on the risk of myocardial infarction (MI) over time and long-term mortality has not been well described. We performed a nationwide population-based cohort study in 27,929 patients who underwent a first isolated CABG between 2000 and 2008 in Sweden. Acute kidney injury was divided into three categories based on the absolute increase in postoperative serum creatinine (sCr) concentration compared with the preoperative baseline: stage 1, sCr increase of 0.3 to 0.5mg/dL; stage 2, sCr increase of >0.5 to 1.0mg/dL and stage 3, sCr increase of ≥1.0mg/dL. The overall incidence of postoperative AKI was 13%, 6.3% met the criterion for stage 1, 4.3% for stage 2 and 2.3% for stage 3. During a mean follow-up of 5.0years, there were 2119 (7.6%) MIs and 4679 (17%) deaths. Multivariable adjusted hazard ratios with 95% confidence intervals for MI were 1.35 (1.15 to 1.57), 1.80 (1.53 to 2.13) and 1.63 (1.29 to 2.07), in AKI stages 1, 2 and 3, respectively. The corresponding hazard ratios for all-cause mortality were 1.30 (1.17 to 1.44), 1.65 (1.48 to 1.83) and 2.68 (2.37 to 3.03), respectively. Our results show that AKI after CABG is associated with an increased long-term risk of MI and death.
    International journal of cardiology 01/2014; 172(1). DOI:10.1016/j.ijcard.2014.01.013 · 6.18 Impact Factor
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    ABSTRACT: Scientific knowledge on disability pension (DP) after revascularization by coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) is scarce. The aim was to study the incidence of and risk factors for being granted DP in the 5 years following a first CABG or PCI, accounting for socio-demographic and medical factors. This is a nationwide population-based study using Swedish registers including all patients 30-63 years of age (n = 34,643, 16.4% women) who had a first CABG (n = 14,107) or PCI (n = 20,536) during 1994-2003. All were alive and without reintervention 30 days after the procedure and were not on DP or old-age pension. Multivariable adjusted Cox proportional hazard ratios (HR) for DP were estimated with 95% confidence intervals (CI). In 5 years following revascularization, 32.4% had been granted DP and the hazard ratio (HR) was higher in women (HR 1.55, 95% CI 1.48-1.62), and in CABG patients compared with PCI patients (HR 1.35, 95% CI 1.30-1.40). Long-term sick leave in the year before intervention was the strongest predictor for DP following revascularization. After adjustments for socio-demographic factors and sick-leave days in the 12 months before revascularization, HR remained high in all patients with diabetes mellitus regardless of type of revascularization. DP after coronary revascularization was common, especially among women and CABG patients. Most studied medical covariates, including mental and musculoskeletal disorders, were risk factors for future DP, especially long-term sickness absence.
    European Journal of Preventive Cardiology 01/2014; DOI:10.1177/2047487313518472 · 2.68 Impact Factor
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    ABSTRACT: Commercial airline crew is one of the occupational groups with the highest exposures to ionising radiation. Crew members are also exposed to other physical risk factors and subject to potential disruption of circadian rhythms. This study analyses mortality in a pooled cohort of 93 771 crew members from 10 countries. The cohort was followed for a mean of 21.7 years (2.0 million person-years), during which 5508 deaths occurred. The overall mortality was strongly reduced in male cockpit (SMR 0.56) and female cabin crews (SMR 0.73). The mortality from radiation-related cancers was also reduced in male cockpit crew (SMR 0.73), but not in female or male cabin crews (SMR 1.01 and 1.00, respectively). The mortality from female breast cancer (SMR 1.06), leukaemia and brain cancer was similar to that of the general population. The mortality from malignant melanoma was elevated, and significantly so in male cockpit crew (SMR 1.57). The mortality from cardiovascular diseases was strongly reduced (SMR 0.46). On the other hand, the mortality from aircraft accidents was exceedingly high (SMR 33.9), as was that from AIDS in male cabin crew (SMR 14.0). This large study with highly complete follow-up shows a reduced overall mortality in male cockpit and female cabin crews, an increased mortality of aircraft accidents and an increased mortality in malignant skin melanoma in cockpit crew. Further analysis after longer follow-up is recommended.
    Occupational and environmental medicine 01/2014; 71(5). DOI:10.1136/oemed-2013-101395 · 3.23 Impact Factor
  • Clinical Gastroenterology and Hepatology 01/2014; 12(1):159. DOI:10.1016/j.cgh.2013.09.037 · 6.53 Impact Factor
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    ABSTRACT: Observational studies have indicated that high calcium intake may prevent colorectal cancer, but as for randomized trials the results are inconclusive. Meanwhile, limited data on the link between serum calcium and cancer risk is available. We investigated the relation between serum calcium and risk of different gastrointestinal cancers in a prospective study. A cohort based on 492,044 subjects with baseline information on calcium (mmol/L) and albumin (g/L) was selected from the Swedish Apolipoprotein MOrtality RISk (AMORIS) study. Multivariable Cox proportional hazard models were used to analyse associations between standardised levels, quartiles and age/sex-specific categories of serum calcium and risk of oesophageal, stomach, colon,rectal cancer and also colorectal cancer combined, while taking into account serum albumin and other comorbidities. During 12 years of follow-up, we identified 323 incident oesophageal cancers, 782 stomach cancers, 2519 colon cancers, and 1495 rectal cancers. A positive association was found between albumin-adjusted serum calcium and risk of oesophageal [HR: 4.82 (95% CI: 2.07 -- 11.19) for high compared to normal age-specific calcium levels] and colon cancer [e.g. HR: 1.07 (95% CI: 1.00 -- 1.14) for every SD increase of calcium] as well as colorectal cancer [e.g. HR: 1.06 (95% CI: 1.02-1.11) for every SD increase of calcium] in women. In men there were similar but weaker non-statistically significant trends. The positive relation between serum calcium, oesophageal cancer and colorectal cancer calls for further studies including calcium regulators to evaluate whether there is a true link between calcium metabolism and development of gastrointestinal cancer.
    BMC Public Health 07/2013; 13(1):663. DOI:10.1186/1471-2458-13-663 · 2.32 Impact Factor
  • Annals of Oncology 06/2013; 24(suppl 4):iv18-iv19. DOI:10.1093/annonc/mdt201.19 · 6.58 Impact Factor
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    ABSTRACT: Background Both dietary and serum levels of inorganic phosphate (Pi) have been linked to development of cancer in experimental studies. This is the first population-based study investigating the relation between serum Pi and risk of cancer in humans. Methods From the Swedish Apolipoprotein Mortality Risk (AMORIS) study, we selected all participants (> 20 years old) with baseline measurements of serum Pi, calcium, alkaline phosphatase, glucose, and creatinine (n = 397,292). Multivariable Cox proportional hazards regression analyses were used to assess serum Pi in relation to overall cancer risk. Similar analyses were performed for specific cancer sites. Results We found a higher overall cancer risk with increasing Pi levels in men ( HR: 1.02 (95% CI: 1.00-1.04) for every SD increase in Pi), and a negative association in women (HR: 0.97 (95% CI: 0.96-0.99) for every SD increase in Pi). Further analyses for specific cancer sites showed a positive link between Pi quartiles and the risk of cancer of the pancreas, lung, thyroid gland and bone in men, and cancer of the oesophagus, lung, and nonmelanoma skin cancer in women. Conversely, the risks for developing breast and endometrial cancer as well as other endocrine cancer in both men and women were lower in those with higher Pi levels. Conclusions Abnormal Pi levels are related to development of cancer. Furthermore, the in verse association between Pi levels and risk of breast, endometrial and other endocrine cancers may indicate the role of hormonal factors in the relation between Pi metabolism and cancer.
    BMC Cancer 05/2013; 13(1):257. DOI:10.1186/1471-2407-13-257 · 3.32 Impact Factor
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    ABSTRACT: Objectives Pre-clinical studies have shown that iron can be carcinogenic, but few population-based studies investigated the association between markers of the iron metabolism and risk of cancer while taking into account inflammation. We assessed the link between serum iron (SI), total-iron binding capacity (TIBC), and risk of cancer by levels of C-reactive protein (CRP) in a large population-based study (n = 220,642). Methods From the Swedish Apolipoprotein Mortality Risk (AMORIS) study, we selected all participants (>20 years old) with baseline measurements of serum SI, TIBC, and CRP. Multivariate Cox proportional hazards regression was carried out for standardized and quartile values of SI and TIBC. Similar analyses were performed for specific cancers (pancreatic, colon, liver, respiratory, kidney, prostate, stomach, and breast cancer). To avoid reverse causation, we excluded those with follow-up <3 years. Results We found a positive association between standardized TIBC and overall cancer [HR 1.03 (95 % CI 1.01–1.05)]. No statistically significant association was found between SI and cancer risk except for postmenopausal breast cancer [HR for standardized SI 1.09 (95 % CI 1.02–1.15)]. The association between TIBC and specific cancer was only statistically significant for colon cancer [i.e., HR for standardized TIBC: 1.17 (95 % CI 1.08–1.28)]. A borderline interaction between SI and levels of CRP was observed only in stomach cancer. Conclusions As opposed to pre-clinical findings for serum iron and cancer, this population-based epidemiological study showed an inverse relation between iron metabolism and cancer risk. Minimal role of inflammatory markers observed warrants further study focusing on developments of specific cancers.
    Cancer Causes and Control 05/2013; 24(7). DOI:10.1007/s10552-013-0219-8 · 2.96 Impact Factor
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    ABSTRACT: OBJECTIVE: The aim was to investigate country or region of birth-specific prevalence and gender differences of diabetes in residents in Sweden, using Swedish-born men and women as referent. METHODS: The Apolipoprotein MOrtality RISk (AMORIS) cohort was used (184,000 men and 151,453 women) aged between 20 and 80 years, with data from the CALAB laboratory, Stockholm, 1985-1996. Diabetes was defined as fasting glucose ≥7.0mmol/L or a hospital diagnosis of diabetes. Country of birth was obtained by linkage to Swedish Censuses 1970-1990. Standardized prevalence rate ratios (SPRR) with 95% confidence intervals (95% CI) were estimated. RESULTS: Five groups of women and one group of men had a significantly higher prevalence than Swedish-born (based on SPRR): women born in Iraq (6.0 (95% CI 1.3-28.9)), North Africa (6.9 (95% CI 3.1-15.3)), South Asia (3.1 (95% CI 1.0-10.0)), Syria (5.3 (95% CI 1.8-16.0)), Turkey (3.7 (95% CI 1.2-10.9)) and men born in other Middle Eastern countries (2.3 (95% CI 1.0-5.5)). Swedish-born men had a higher age-standardized prevalence of diabetes (3.9%) than Swedish born women (2.5%). A higher prevalence among men was also seen in other Western countries. In contrast, a higher age-standardized prevalence among women was observed in immigrants from Turkey (8.9% vs. 3.1%, p<0.001), Syria (13.1% vs. 4.0%, p=0.002), and North Africa (16.8% vs. 6.6%, p<0.001). CONCLUSION: Female immigrants to Sweden from Iraq, North Africa, South Asia, Syria, and Turkey have an increased prevalence of diabetes of substantial public health concern.
    Diabetes research and clinical practice 04/2013; 100(3). DOI:10.1016/j.diabres.2013.03.014 · 2.54 Impact Factor

Publication Stats

4k Citations
838.20 Total Impact Points

Institutions

  • 1991–2015
    • Karolinska Institutet
      • Institute of Environmental Medicine - IMM
      Сольна, Stockholm, Sweden
  • 2012
    • King's College London
      • Division of Cancer Studies
      London, ENG, United Kingdom
  • 2006–2012
    • AstraZeneca
      Tukholma, Stockholm, Sweden
  • 2011
    • University of Oslo
      Kristiania (historical), Oslo County, Norway
  • 2008
    • Norwegian Institute of Public Health
      • Division of Epidemiology
      Kristiania (historical), Oslo County, Norway
  • 2004
    • Public Health Agency of Sweden
      Tukholma, Stockholm, Sweden
  • 2000–2004
    • Karolinska University Hospital
      Tukholma, Stockholm, Sweden
  • 1983–2003
    • University of Helsinki
      • • Department of Dental Public Health
      • • Department of Public Health Science
      Helsinki, Uusimaa, Finland
  • 2002
    • University of Turku
      Turku, Varsinais-Suomi, Finland
  • 1998
    • Stockholm County Council
      Tukholma, Stockholm, Sweden
    • Sahlgrenska University Hospital
      Goeteborg, Västra Götaland, Sweden