Risk factors for multiple myeloma: A hospital-based case-control study in Northwest China

BackgroundThe distinctive racial/ethnic and geographic distribution of multiple myeloma (MM) suggests that both family history and environmental factors may contribute to its development.MethodsA hospital-based case–control study consisting of 220 confirmed MM cases and 220 individually matched patient controls, by sex, age and hospital was carried out at 5 major hospitals in Northwest China. A questionnaire was used to obtain information on demographics, family history, and the frequency of food items consumed.ResultsBased on multivariate analysis, a significant association between the risk of MM and family history of cancers in first degree relatives was observed (OR = 4.03, 95% CI: 2.50–6.52). Fried food, cured/smoked food, black tea, and fish were not significantly associated with the risk of MM. Intake of shallot and garlic (OR = 0.60, 95% CI: 0.43–0.85), soy food (OR = 0.52, 95% CI: 0.36–0.75) and green tea (OR = 0.38, 95% CI: 0.27–0.53) was significantly associated with a reduced risk of MM. In contrast, intake of brined vegetables and pickle was significantly associated with an increased risk (OR = 2.03, 95% CI: 1.41–2.93). A more than multiplicative interaction on the decreased risk of MM was found between shallot/garlic and soy food.ConclusionOur study in Northwest China found an increased risk of MM with a family history of cancer, a diet characterized by low consumption of garlic, green tea and soy foods, and high consumption of pickled vegetables. The effect of green tea in reducing the risk of MM is an interesting new finding which should be further confirmed.     

Risk factors for severe malaria in Bamako, Mali: a matched case-control study

The aim of this case-control study was to identify epidemiological risk factors for severe malaria among children living in Bamako, a malaria-endemic area. For this, 260 healthy community controls were matched to 130 patients with severe malaria. Conditional multiple logistic regression analysis indicated that all examined independent factors associated with severe malaria are directly related to characteristics of the child's mother, with the exception of the child's own yellow fever vaccination history (odds ratio (OR): 1.93, 95% confidence intervals (CI(95%)) [1.10-3.37]). The following characteristics were all associated with a decreased risk of severe malaria in the child: maternal education (OR: 0.52, CI(95%) [0.31-0.86]), the mother's adequate knowledge about malaria (OR: 0.46, 95% CI(95%) [0.25-0.86]), her use of mosquito bed nets (OR: 0.53, CI(95%) [0.30-0.92]) and breast-feeding for at least 2 years (OR: 0.57, CI(95%) [0.33-0.94]). Conversely, chronic maternal disease (OR: ?3.16, CI(95%) [1.31-7.61]) was associated with an increased risk of severe malaria. These findings strongly support the hypothesis that maternal factors are central to the development of severe malaria in children. Programmes aiming to improve both maternal health and maternal education may reduce the incidence of severe malaria in children and should therefore be advocated in Bamako and in areas with similar epidemiological patterns for malaria.     

Risk factors for preeclampsia in women from Colombia: a case-control study

Background

Preeclampsia (PE) is a multi-causal disease characterized by the development of hypertension and proteinuria in the second half of pregnancy. Multiple risk factors have been associated with the development of PE. Moreover, it is known that these risk factors vary between populations from developed and developing countries. The aim of this study is to identify which risk factors are associated with the development of preeclampsia (PE) among Colombian women.

Methods

A multi-centre case-control study was conducted between September 2006 and July 2009 in six Colombian cities. Cases included women with PE (n = 201); controls were aged-matched pregnant women (n = 201) without cardiovascular or endocrine diseases for a case-control ratio of 1∶1. A complete medical chart, physical examination and biochemical analysis were completed before delivery. Multivariable logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI) of potential risk factors associated with PE.

Results

The presence of factors present in the metabolic syndrome cluster such as body mass index >31 Kg/m2 (OR = 2.18; 1.14–4.14 95% CI), high-density lipoprotein <1.24 mmol/L (OR = 2.42; 1.53–3.84 95% CI), triglycerides >3.24 mmol/L (OR = 1.60; 1.04–2.48 95% CI) and glycemia >4.9 mmol/L (OR = 2.66; 1.47–4.81 95%CI) as well as being primigravidae (OR = 1.71; 1.07–2.73 95% CI) were associated with the development of PE, after adjusting for other variables.

Conclusion

Factors present in the cluster of metabolic syndrome and primigravidity were associated with a greater risk of PE among Colombian women. Understanding the role of this cluster of risk factors in the development of PE is of crucial importance to prevent PE and remains to be determined.     

Risk factors for neonatal encephalopathy in Kathmandu, Nepal, a developing country: unmatched case-control study

This unmatched case-control study determined the risk factors for neonatal encephalopathy among term infants in Kathmandu, Nepal. Study participants included 131 infants with neonatal encephalopathy born between January 1995 and July 1996, and 635 unmatched infants systematically recruited over 12 months. The prevalence of neonatal encephalopathy was 6.1% per 1000 live births, of which 63% were infants with moderate encephalopathy. Antepartum risk factors included multiple births (odds ratio, OR = 22), primiparity (OR = 2.0), and nonattendance for antenatal care (OR = 2.1). Intrapartum risk factors were particulate meconium (OR = 18), noncephalic presentation (OR = 3.4), prolonged rupture of membranes (OR = 3.8), and other complications. In addition, induction of labor with oxytocin was associated with encephalopathy in 12 of 41 deliveries (OR = 5.7). Overall, 78 affected infants (60%) compared with 36 controls (6%) either had evidence of intrapartum compromise or were born after an intrapartum difficulty likely to result in fetal compromise. Moreover, maternal hemoglobin concentration 8.0 g/dl (OR = 2.5) and thyroid stimulating hormone 5 ml U/l (OR = 2.1) were associated with encephalopathy. Intrapartum risk factors remain important for neonatal encephalopathy in developing countries. There is some evidence of a protective effect from antenatal care. The use of oxytocin in low-income countries where intrapartum monitoring is suboptimal presents a major risk to the fetus. Further studies are required to explore the association between maternal deficiency states and neonatal encephalopathy.     

Risk factors for low birth weight: Results from a case-control study in southern Spain

The main objective of this study is to examine the effect of several variables, including altitude of maternal residence, on delivering a low birth weight (LBW) newborn. A case-control study was done. Two hundred forty cases (single newborn weighing less than 2,500 g) and 374 controls (single newborn weighing more than 2,499 g) were included. Information was gathered from the clinical chart of delivering women, through a personal interview and the Spanish Census Bureau (for altitude). Predictors of LBW were assessed through stepwise logistic regression analysis. Several well-known LBW risk factors were identified: hypertension, weight gain during pregnancy, body size (mainly maternal prepregnancy weight), low social class, primiparity, and several conditions (spontaneous delivery, abruptio placentae). Altitude was an independent predictor of LBW at term (more than 37 weeks of gestational age) but not for preterm LBW. Nevertheless, a relationship between altitude and birth weight was not found in controls, although a moderate decreasing gradient with altitude was observed. The limitations of these findings are discussed. Am J Phys Anthropol 105:419–424, 1998. © 1998 Wiley-Liss, Inc.     

Risk factors in autism spectrum disorder: A Tunisian case-control study

BackgroundAutism spectrum disorder (ASD) is a neurodevelopmental condition that causes disability in social interaction, communication, and restrictive and repetitive behaviors. Common environmental factors like prenatal, perinatal, and/or postnatal factors play a key role in ASD etiologies. Moreover, specific metabolic disorders can be associated with ASD.Subjects and methodsWe performed a retrospective case-control study in child psychiatry clinics, involving 51 children with ASD and 40 typical development controls (TDC).ResultsWe found a correlation between children being breastfed for less than 6 months, having fathers more than 40 years old at childbirth in ASD compared to TDC group. Our study also associated low blood cholesterol and low erythrocyte magnesium levels with increased risk for ASD.ConclusionFindings support the implication of total cholesterol (TC) and erythrocyte magnesium level in defining autism outcome.     

Risk factors for winter outbreak of acute diarrhoea in France: case-control study.

OBJECTIVES: To assess the potential role of consumption of shellfish (particularly raw oysters) and tap water in the winter epidemic of acute diarrhoea in France. DESIGN: Population based, case-control study during the 1995-6 winter epidemic of acute diarrhoea in France. SETTING: A national network comprising 1% of general practitioners in France. SUBJECTS: 568 pairs of cases and controls consulting in general practice and interviewed by 209 doctors from 26 December 1995 to 31 January 1996. Cases and controls were matched for age, doctor, and time of consultation. MAIN OUTCOME MEASURES: Adjusted relative risk of diarrhoea estimated from conditional logistic regression. RESULTS: The risk of acute diarrhoea was not increased in people who had recently eaten raw oysters (odds ratio 1.1; 95% confidence interval 0.9% to 1.4%) or other shellfish such as clams, cockles, and mussels, or in those people who usually consumed tap water rather than bottled water (0.8; 0.6% to 1.1%). The risk was, however, increased in people who had had recent contact wit ha person with diarrhoea either within the household (adjusted odds ratio 5.0) or in the workplace (3.1), and in people who lived with a child < or = 2 years of age (1.6). Recent treatment with either oral penicillin or cephalosporin was also independently associated with acute diarrhoea in winter. CONCLUSIONS: The winter epidemic of acute diarrhoea in France is probably not caused by consumption of either shellfish or tap water. A viral aetiology, however, is suggested by the speed with which the acute diarrhoea is transmitted.     

Risk factors for breast cancer in women biopsied for benign breast disease: A nested case-control study

Aim: Women with a history of benign breast disease are at increased risk of subsequent breast cancer. However, few studies have examined whether established breast cancer risk factors other than histology are associated with an altered risk of breast cancer in women with benign breast disease. We used a nested case-control design within a large, multi-center cohort of women biopsied for benign breast disease (BBD) to estimate odds ratios for breast cancer in association with exposure to a range of personal and lifestyle factors. Methods: Cases were women biopsied for BBD who subsequently developed breast cancer; controls were individually matched to cases on center and age at diagnosis and were women biopsied for BBD who did not develop breast cancer in the same follow-up interval as that for the cases. After excluding women with prevalent breast cancer, 1357 records (661 case records and 696 records) were available for analysis. We used conditional logistic regression to obtain crude and multivariable-adjusted estimates of the association between specific factors and risk of breast cancer. Results: In multivariable analyses age at first live birth, number of pregnancies, and postmenopausal status were inversely associated with risk of breast cancer. The odds ratio for women with age at first birth <25 years and ≥3 pregnancies, relative to nulliparous women, was 0.49, 95% confidence interval 0.13–0.79, and that for postmenopausal women relative to premenopausal women was 0.60, 95% CI 0.37–0.99. Conclusions: Further study of personal factors influencing the risk of breast cancer in women with BBD may help to identify subgroups of the population at increased risk of invasive disease.     

Prognostic factors for esophageal squamous cell carcinoma--a population-based study in Golestan Province, Iran, a high incidence area

Golestan Province in northern Iran is an area with a high incidence of esophageal squamous cell carcinoma (ESCC). We aimed to investigate prognostic factors for ESCC and survival of cases in Golestan, on which little data were available. We followed-up 426 ESCC cases participating in a population-based case-control study. Data were analyzed using the Kaplan-Meier method and the Cox proportional hazard models. Median survival was 7 months. Age at diagnosis was inversely associated with survival, but the association was disappeared with adjustment for treatment. Residing in urban areas (hazard ratio, HR?=?0.70; 95% CI 0.54-0.90) and being of non-Turkmen ethnic groups (HR?=?0.76; 95% CI 0.61-0.96) were associated with better prognosis. In contrast to other types of tobacco use, nass (a smokeless tobacco product) chewing was associated with a slightly poorer prognosis even in models adjusted for other factors including stage of disease and treatment (HR?=?1.38; 95% CI 0.99-1.92). Opium use was associated with poorer prognosis in crude analyses but not in adjusted models. Almost all of potentially curative treatments were associated with longer survival. Prognosis of ESCC in Golestan is very poor. Easier access to treatment facilities may improve the prognosis of ESCC in Golestan. The observed association between nass chewing and poorer prognosis needs further investigations; this association may suggest a possible role for ingestion of nass constituents in prognosis of ESCC.     

Risk factors for campylobacteriosis of chicken, ruminant, and environmental origin: a combined case-control and source attribution analysis

Background

Campylobacteriosis contributes strongly to the disease burden of food-borne pathogens. Case-control studies are limited in attributing human infections to the different reservoirs because they can only trace back to the points of exposure, which may not point to the original reservoirs because of cross-contamination. Human Campylobacter infections can be attributed to specific reservoirs by estimating the extent of subtype sharing between strains from humans and reservoirs using multilocus sequence typing (MLST).

Methodology/Principal Findings

We investigated risk factors for human campylobacteriosis caused by Campylobacter strains attributed to different reservoirs. Sequence types (STs) were determined for 696 C. jejuni and 41 C. coli strains from endemic human cases included in a case-control study. The asymmetric island model, a population genetics approach for modeling Campylobacter evolution and transmission, attributed these cases to four putative animal reservoirs (chicken, cattle, sheep, pig) and to the environment (water, sand, wild birds) considered as a proxy for other unidentified reservoirs. Most cases were attributed to chicken (66%) and cattle (21%), identified as the main reservoirs in The Netherlands. Consuming chicken was a risk factor for campylobacteriosis caused by chicken-associated STs, whereas consuming beef and pork were protective. Risk factors for campylobacteriosis caused by ruminant-associated STs were contact with animals, barbecuing in non-urban areas, consumption of tripe, and never/seldom chicken consumption. Consuming game and swimming in a domestic swimming pool during springtime were risk factors for campylobacteriosis caused by environment-associated STs. Infections with chicken- and ruminant-associated STs were only partially explained by food-borne transmission; direct contact and environmental pathways were also important.

Conclusion/Significance

This is the first case-control study in which risk factors for campylobacteriosis are investigated in relation to the attributed reservoirs based on MLST profiles. Combining epidemiological and source attribution data improved campylobacteriosis risk factor identification and characterization, generated hypotheses, and showed that genotype-based source attribution is epidemiologically sensible.     

Risk factors for severe cases of 2009 influenza A (H1N1): a case control study in Zhejiang Province, China

Few case control studies were conducted to explore risk factors for severe cases of 2009 influenza A (H1N1) with the mild cases as controls. Mild and severe cases of 2009 influenza A (H1N1), 230 cases each, were randomly selected from nine cities in Zhejiang Province, China, and unmatched case control study was conducted. This study found that it averagely took 5 days for the severe cases of 2009 influenza A (H1N1) to start antiviral therapy away from onset, 2 days later than mild cases. Having chronic underlying diseases and bad psychological health combined with chronic underlying diseases were two important risk factors for severe cases, and their OR values were 2.39 and 5.85 respectively. Timely anti-viral therapy was a protective factor for severe cases (OR = 0.35, 95% CI: [0.18–0.67]). In conclusion, psychological health education and intervention, as well as timely anti-viral therapy, could not be ignored in the prevention, control and treatment of 2009 influenza A (H1N1).     

Risk factors of Streptococcus suis infection in Vietnam. A case-control study

Background

Streptococcus suis infection, an emerging zoonosis, is an increasing public health problem across South East Asia and the most common cause of acute bacterial meningitis in adults in Vietnam. Little is known of the risk factors underlying the disease.

Methods and Findings

A case-control study with appropriate hospital and matched community controls for each patient was conducted between May 2006 and June 2009. Potential risk factors were assessed using a standardized questionnaire and investigation of throat and rectal S. suis carriage in cases, controls and their pigs, using real-time PCR and culture of swab samples. We recruited 101 cases of S. suis meningitis, 303 hospital controls and 300 community controls. By multivariate analysis, risk factors identified for S. suis infection as compared to either control group included eating “high risk” dishes, including such dishes as undercooked pig blood and pig intestine (OR₁ = 2.22; 95%CI = [1.15–4.28] and OR₂ = 4.44; 95%CI = [2.15–9.15]), occupations related to pigs (OR₁ = 3.84; 95%CI = [1.32–11.11] and OR₂ = 5.52; 95%CI = [1.49–20.39]), and exposures to pigs or pork in the presence of skin injuries (OR₁ = 7.48; 95%CI = [1.97–28.44] and OR₂ = 15.96; 95%CI = [2.97–85.72]). S. suis specific DNA was detected in rectal and throat swabs of 6 patients and was cultured from 2 rectal samples, but was not detected in such samples of 1522 healthy individuals or patients without S. suis infection.

Conclusions

This case control study, the largest prospective epidemiological assessment of this disease, has identified the most important risk factors associated with S. suis bacterial meningitis to be eating ‘high risk’ dishes popular in parts of Asia, occupational exposure to pigs and pig products, and preparation of pork in the presence of skin lesions. These risk factors can be addressed in public health campaigns aimed at preventing S. suis infection.     

Circulating microRNAs as diagnostic and therapeutic biomarkers in gastric and esophageal cancers

Gastric and esophageal cancers are as main cancers of the gastrointestinal (GI) tract, which are associated with poor diagnosis and survival. Several efforts were made in the past few decades to finding effective therapeutic approaches, but these approaches had several problems. Finding new biomarkers is a critical step in finding new approaches for the treatment of these cancers. Finding new biomarkers that cover various aspects of the diseases could provide a choice of suitable therapies and better monitoring of patients with these cancers. Among several biomarkers tissue specific and circulating microRNAs (miRNAs) have emerged as powerful candidates in the diagnosis of gastric and esophageal cancers. MiRNAs are small noncoding single‐stranded RNA molecules that are found in the blood and regulate gene expression. These have numerous characteristics that make them suitable for being used as ideal biomarkers in cancer diagnosis. Research has indicated that the level and profile of miRNA in serum and plasma are very high. They are potentially noninvasive and sensitive enough to detect tumors in their primary stages of infection. Multiple lines of evidence indicate that the presence, absence, or deregulation of several circulating miRNAs (i.e., let‐7a, miR‐21, miR‐93, miR‐192a, miR‐18a, and miR‐10b for gastric cancer, and miR‐21, miR‐375, miR‐25‐3p, miR‐151a‐3p, and miR‐100‐3p for esophageal cancer) are associated with initiation and progression of gastric and esophageal cancers. The aim of this review is to highlight the recent advances in the roles of miRNAs in diagnosis and treatment of gastric and esophageal cancers.     

Dietary habits,nutrition and esophageal cancer: A case-control study on Kazakhs in Xinjiang

ObjectiveTo explore associations between dietary habits and esophageal epithelial cell carcinoma (ESCC) and provide a potential direction for exploring how different dietary habits and nutrient intake might affect ESCC development.Methods198 ESCC cases and 200 controls on Kazakhs were recruited in Xinjiang from 2010 to 2019 for a group-matched case-control study. The case group were recruited from the First Affiliated Hospital of Xinjiang Medical University and Affiliated Cancer Hospital of Xinjiang Medical University. The control population were recruited from two parts: hospital-based control and population-based control. The diagnosis was confirmed by histological examination. The food frequency questionnaire was used to investigate the dietary nutrients intake. Folic acid, vitamin B12, and DNA-methyltransferase 1(DNMT1) levels were measured in serum samples obtained from cases and controls.ResultsThe cholesterol intake of ESCC group was significantly higher than that of the control group while the intakes of protein, thiamin, riboflavin, folic acid, vitamin A, B6, C and E were significantly lower than the control group. Factors including lacking fresh vegetables and fruits, low educational level, low income, alcohol drinking, eating solid and dry food and smoked meat, dieting irregularly, salty taste preference, low serum folic acid level and high serum DNMT1 level were associated with increased risk of ESCC in Kazakhs.ConclusionDietary habits and nutrient intake were associated with increased risk of ESCC in Kazakhs that may provide a potential direction for further studies.     

Risk factor for clear cell renal cell carcinoma in Chinese population: a case-control study

Background: Risk factors for clear cell renal cell carcinoma (ccRCC) differ among populations and remain controversial. We carried out a hospital-based case–control study to examine the effects of health status, lifestyle, and some genetic polymorphisms on ccRCC risk in Chinese subjects. Methods: Between 2007 and 2009, 250 newly diagnosed, histologically confirmed ccRCC cases and 299 sex-, age-matched healthy controls provided complete information including consumption of tea and alcohol, smoking, occupational exposure, body mass index (BMI), hypertension, diabetes, and urolithiasis by face-to-face interview in Shanghai. Genetic polymorphisms of cytochrome P450 mono-oxygenase (CYP1A1: 6235T>C, 4889A>G, and 4887C>A), glutathione S-transferase (GSTP1: 342A>G), and N-acetyltransferase (NAT2: 481C>T, 590G>A, and 857G>A) were identified by PCR-RFLP and DNA sequencing. Adjusted odds ratio (AOR) and 95% confidence interval (CI) were derived through multivariate logistic regression. Results: Green tea intake (≥500 ml/d) was inversely associated with ccRCC risk, with an AOR of 0.34 (95% CI 0.21–0.55). BMI (≥25 kg/m²), hypertension, and urolithiasis were independently associated with an increased risk of ccRCC, with AOR (95% CI) of 2.10 (1.32–3.34), 2.49 (1.57–3.93), and 3.33 (1.12–9.89), respectively. No association was observed between smoking, alcohol consumption, or occupational exposure with ccRCC risk. The polymorphisms and their interactions with the environmental exposures were mostly not associated with ccRCC risk. Conclusion: BMI (≥25 kg/m²), hypertension, and urolithiasis are independently associated with an increased risk, whereas green tea intake (≥500 ml/d) is independently associated with a decreased risk of ccRCC. The polymorphisms of the xenobiotic-metabolizing enzymes are weakly associated with ccRCC risk in Chinese subjects.     

山西省金藻植物新纪录

通过对山西所采集的金藻植物标本的鉴定和统计整理,共报道山西省金藻植物新纪录34种1变种,隶属于6科15属。对这些藻类植物的形态、生境和地理分布做了简要描述,凭证标本存放于山西大学生命科学学院标本室(SXU)。     

Risk factors for physical disability in patients with leprosy disease in Yunnan,China: Evidence from a retrospective observational study

BackgroundLeprosy is potentially debilitating. The risk factors related to physical disabilities associated with leprosy disease in Yunnan, China was not clear.Methodology/Principal findingsWe studied 10644 newly detected leprosy patients from Yunnan, China, from 1990 to 2019. Factors associated with Grade 1 (G1D) and Grade 2 (G2D) physical disabilities or overall physical disabilities (combined G1D and G2D) associated with leprosy were analyzed using multinomial and ordinal logistic regression analyses. The following factors were associated with the development of physical disability in these patients with leprosy: delayed diagnosis [odds ratio (OR): 5.652, 4.399, and 2.275; 95% confidence intervals (CIs): 4.516–7.073, 3.714–5.212, and 2.063–2.509; for ≥ 10, 5–10 y, and 2–5 years, respectively], nerve damage (OR: 3.474 and 2.428; 95% CI: 2.843–4.244, and 1.959–3.008; for 2 and 1 damaged nerves, respectively), WHO classification of PB (OR: 1.759; 95% CI: 1.341–2.307), Ridley-Jopling classification (OR: 1.479, 1.438, 1.522 and 1.239; 95% CI: 1.052–2.079, 1.075–1.923, 1.261–1.838, and 1.072–1.431; for TT, BT, BB, and BL when compared with LL, respectively), advanced age (OR: 1.472 and 2.053; 95% CI: 1.106–1.960 and 1.498–2.814; for 15–59 and over 60 years old, respectively), zero skin lesions (OR: 1.916; 95% CI: 1.522–2.413), leprosy reaction (OR: 1.528; 95% CI: 1.195–1.952), rural occupation (OR: 1.364; 95% CI: 1.128–1.650), Han ethnicity (OR: 1.268; 95% CI: 1.159–1.386), and male sex (OR: 1.128; 95% CI: 1.024–1.243).ConclusionsDelayed diagnosis, nerve damage, no skin lesions, WHO and Ridley-Jopling classifications, leprosy reactions, advanced age, rural occupation, Han ethnicity, and male sex were associated with disability in leprosy patients. Identifying risk factors could help to prevent physical disability.     

Individual and occupational risk factors for knee osteoarthritis: results of a case-control study in Germany

Introduction

A number of occupational risk factors are discussed in relation to the development and progress of knee joint diseases (for example, working in a kneeling or squatting posture, lifting and carrying heavy weights). Besides the occupational factors, a number of individual risk factors are important. The distinction between work-related and other factors is crucial in assessing the risk and in deriving preventive measures in occupational health.

Methods

In a case-control study, patients with and without symptomatic knee osteoarthritis (OA) were questioned by means of a standardised questionnaire complemented by a semi-standardised interview. Controls were matched and assigned to the cases by gender and age. Conditional logistic regression was used in analysing data.

Results

In total, 739 cases and 571 controls were included in the study. In women and men, several individual and occupational predictors for knee OA could be described: obesity (odds ratio (OR) up to 17.65 in women and up to 12.56 in men); kneeling/squatting (women, OR 2.52 (>8,934 hours/life); men, 2.16 (574 to 12,244 hours/life), 2.47 (>12,244 hours/life)); genetic predisposition (women, OR 2.17; men, OR 2.37); and sports with a risk of unapparent trauma (women, OR 2.47 (≥1,440 hours/life); men, 2.58 (≥3,232 hours/life)). In women, malalignment of the knee (OR 11.54), pain in the knee already in childhood (OR 2.08), and the daily lifting and carrying of loads (≥1,088 tons/life, OR 2.13) were related to an increased OR; sitting and smoking led to a reduced OR.

Conclusions

The results support a dose-response relationship between kneeling/squatting and symptomatic knee OA in men and, for the first time, in women. The results concerning general and occupational predictors for knee OA reflect the findings from the literature quite well. Yet occupational risks such as jumping or climbing stairs/ladders, as discussed in the literature, did not correlate with symptomatic knee OA in the present study. With regards to occupational health, prevention measures should focus on the reduction of kneeling activities and the lifting and carrying of loads as well as general risk factors, most notably the reduction of obesity. More intervention studies of the effectiveness of tools and working methods for reducing knee straining activities are needed.