Public Health Center-based Prospective Study Research Articles

Low-intensity cigarette smoking and mortality risks.

In ‘Low-intensity cigarette smoking and mortality risks: a pooled analysis of prospective cohort studies in Japan’, the authors pool multiple prospective cohort studies to assess the relationship between low-intensity smoking and mortality risk. This study refutes the common belief that low-intensity smoking is not harmful and found a higher risk of mortality among all causes in low-intensity smokers versus never smokers.1 However, the study could be improved in the following ways. Although the authors do acknowledge that the cohorts included in this study only included a smoking status assessment at baseline (with the exception of the Japan Public Health Center-based Prospective Study Cohorts I and II, which re-assessed smoking status at 5 years of follow-up), the study could be improved with more elaboration regarding the impact of this limitation on the study findings. The authors discuss the large decline in smoking prevalence over the recent decades and make the claim that it is likely that many participants reduced or quit smoking, which would improve the observed effect measures; however, all cohorts included individuals over 40 years of age at the time of enrollment, with no stratification by the authors to account for differences in smoking habits by age groups. Research is still unclear as to whether or not the elderly are just as likely as the general population to quit or reduce their smoking. A study conducted in South Korea found that advancing age was not associated with a decline in prevalence of smokers, regardless of gender.2 Given that the readers cannot ascertain the age distribution of the included cohorts from the article, it is difficult to tell whether or not the majority of included participants fall into the age range of elderly or if most are between 40 and 64 years of age. If many of the participants were elderly at baseline, it cannot be safely assumed that many of them quit or reduced their smoking during the follow-up period.

Association between working hours and cancer risk in Japan: The Japan public health center-based prospective study

In this study, we evaluated the association between working hours and cancer risk in the Japanese population, which has not been evaluated. Using a cohort database from a Japan Public Health Center-based Prospective Study, we evaluated 26 738 participants (16 351 men and 10387 women), who responded to a questionnaire about working hours and followed these participants from 1993-1994 to 2013. Participants were divided into four groups according to working hours (≤6, 7-8, 9-10, ≥11 h/day). The hazard ratio (HR) and 95% confidence interval (CI) of each cancer incidence were calculated using a multivariable-adjusted Cox proportional hazard model. During 488 383 person-years of follow-up, 481 patients with newly diagnosed cancers were identified. There was no clear association between long working hours and overall cancer, lung cancer, and stomach cancer risks. Long working hours tended to increase prostate cancer risk in men and breast cancer risk in women, although the difference was not statistically significant. Increased liver cancer risk with short working hours (HR [95% CI]; 3.15 [1.44-6.88] in the ≤6h/day group vs. 7-8 h/day) was observed. Colorectal cancer also tended to increase risk in short working hours, however, there were not statistically significance. In this population, long working hours were not associated with cancer risk with statistically significance. The association between short working hours and liver cancer risk was observed, probably due to the reverse causation of liver cancer.

Circulating Inflammation Markers and Pancreatic Cancer Risk: A Prospective Case-Cohort Study in Japan.

Previous prospective studies of associations between circulating inflammation-related molecules and pancreatic cancer risk have included limited numbers of markers. We conducted a case-cohort study nested within the Japan Public Health Center-based Prospective Study Cohort II. We selected a random subcohort (n = 774) from a total of 23,335 participants aged 40 to 69 years who returned a questionnaire and provided blood samples at baseline. During the follow-up period from 1993 to 2010, we identified 111 newly diagnosed pancreatic cancer cases, including one case within the subcohort. Plasma concentrations of 62 inflammatory markers of chemokines, cytokines, and growth factors were measured by a Luminex fluorescent bead-based assay. Cox regression models were applied to estimate HR and 95% confidence intervals (CI) for pancreatic cancer risk for quartiles of marker levels adjusted for potential confounders. The HR (95% CI) for the highest versus the lowest category of C-C motif ligand chemokine 8/monocyte chemoattractant protein 2 (CCL8/MCP2) was 2.03 (1.05-3.93; P trend = 0.048). After we corrected for multiple comparisons, none of the examined biomarkers were associated with pancreatic cancer risk at P-value <0.05. We found no significant associations between 62 inflammatory markers and pancreatic cancer risk. The suggestive association with circulating levels of leukocyte recruiting cytokine CCL8/MCP2 may warrant further investigation.

COT-6 Body mass index and height in relation to brain tumor risk in a Japanese population

Purpose: Because the prognosis of the malignant brain tumor including glioblastoma is extremely worse than other cancer, it is important to clarify the preventive factors of the brain tumor in the prospective cohort study. In the Japanese epidemiologic study of the brain tumor, the report of the prospective cohort study has not been accomplished. Therefore, we have reported the study in recent years from a multipurpose cohort study (Japan Public Health Center-based Prospective Study: JPHC study) that the national cancer center was mainly conducted. This prospective study investigated the association between height and BMI (Body mass index) and brain tumor risk in an Asian population, whose distribution of anthropometric data differs from Westerners. Methods: A total of 106,324 subjects (50,438 men and 55,886 women) enrolled in JPHC Study, was followed from 1990. We divided participants into 5 categories based on the distribution of BMI as <18.5, 18.5- <23, 23- <25, 25- <27.5, and >-27.5 Kg/m2. We used the Cox proportional hazards regression model and estimated brain tumor incidence by gender and tumor subtype, with adjustment for potential confounding variables; age, sex, pack-years of cigarette smoking, alcohol intake, coffee intake, green tea intake, past history of allergy and past history of diabetes mellitus.Results: During an average follow-up of 18.1 years, 157 incident cases of brain tumor were newly identified, included glioma (n=60), meningioma (n =51), lymphoma(n=9), schwannoma(n=3), pituitary adenoma(n=2), and others(n=32). Higher BMI was significantly positively associated with the risk of brain tumor. This positive association of BMI was stronger in men and for meningioma in subgroup analyses. In contrast, height showed no clear association with brain tumor risk. Conclusion: Higher BMI was associated with an increased risk of brain tumor, in particular of meningioma, and among men.Full article has been published annals of epidemiology.

Sugary drink consumption and risk of kidney and bladder cancer in Japanese adults

Globally, sugary drinks are widely consumed, however, few epidemiologic studies have investigated the association between sugary drink consumption and risk of kidney and bladder cancer. We examined the association of sugary drinks with risk of kidney and bladder cancer in 73,024 participants from the Japan Public Health Center-based Prospective Study who reported no history of cancer. Sugary drink consumption was assessed using a validated food frequency questionnaire at study baseline (1995–1999). Individuals were followed to December 31, 2013. Multivariable Cox proportional hazards regression models were used to calculate hazard ratios (HR) and 95% confidence intervals (CIs). During 1,069,815 person years of follow-up, 169 kidney cancer and 297 bladder cancer cases were documented. After adjusting for potential confounders, no greater risk of kidney and bladder cancer was observed. However, sugary drink consumption was positively associated with the risk of kidney cancer (HR for 100 ml/day increase in consumption was 1.11 [95% CI 1.01–1.22]) and bladder cancer (HR for 100 ml/d increase in consumption was 1.11 [95% CI 1.01–1.22]) among women after exclusion of cases diagnosed in the first three years of follow-up. In this large prospective cohort, consumption of sugary drinks was significantly associated with a small increase in hazard ratio for kidney and bladder cancer among women after exclusion of cases diagnosed within the first three years.

November 2021 Stroke Highlights

November 2021 <i>Stroke</i> Highlights

Alcohol consumption, tobacco smoking, and subsequent risk of renal cell carcinoma: The JPHC study.

The effects of alcohol consumption and tobacco smoking on renal cell carcinoma (RCC) incidence have not been well‐investigated in Asian populations. Here, we evaluated these effects in a large Japanese prospective cohort. We collected data on eligible participants in the Japan Public Health Center‐based Prospective Study, and undertook multivariable‐adjusted Cox proportional hazards regression to estimate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) of RCC incidence. We identified 340 cases (230 men and 110 women) among the 105 663 eligible participants (50 262 men and 55 741 women), who were followed for an average of 19.1 years, with a cumulative total of 2 020 364 person‐years. A slightly inverse but nonsignificant association was observed between alcohol drinking and RCC incidence. In contrast, the risk of RCC was increased in those with heavy smoking (≥40 pack‐years) when men and women were combined (HR 1.50; 95% CI, 1.01‐2.25). We identified no significant association between alcohol consumption and RCC incidence. In contrast, heavy smoking (≥40 pack‐years) was associated with a significant increase in incidence.

Association between sugar and starch intakes and type 2 diabetes risk in middle-aged adults in a prospective cohort study.

We aimed to investigate the association between sugar or starch intake and the risk of type 2 diabetes (T2D) in middle-aged Japanese adults. Participants comprised 27,797 men and 36,880 women aged 45-75 years with no history of diabetes and critical illness before the second survey in the Japan Public Health Center-based Prospective Study. We calculated sugar (total sugar, total fructose, and sugar subtypes) and starch intakes (% energy/d) using a validated 147-item food frequency questionnaire, to estimate the average dietary intake over the previous year. T2D onset was defined by validated self-reports. ORs adjusted for potential confounders were estimated using multiple logistic regression with categorical and cubic spline models. During the 5-year follow-up, 690 men and 500 women were identified with T2D. In women, the quartiles of total sugar or total fructose intakes were not significantly associated with T2D risk; however, the spline curves showed an increased risk at extremely high intake levels (ORs [95% CI]: 1.88 [1.07-3.31] at 30% energy/d for total sugar and 1.87 [1.10-3.16] at 14% energy/d for total fructose). Starch intake was positively associated with T2D risk among women in the categorical and spline models (ORs [95% CI]: 1.55 [1.13-2.12] at 50% energy/d). In men, sugar and starch intakes were not associated with T2D risk. In this large-scale population-based cohort study, starch intake was associated with an increased T2D risk in Japanese women. An increased risk with extremely high intake of total sugar or total fructose among women cannot be disregarded.

Erratum: Relation Between Body Mass Index and Dry Eye Disease: The Japan Public Health Center-Based Prospective Study for the Next Generation.

Erratum: Relation Between Body Mass Index and Dry Eye Disease: The Japan Public Health Center-Based Prospective Study for the Next Generation.

Association of dietary intakes of vitamin B12, vitamin B6, folate, and methionine with the risk of esophageal cancer: the Japan Public Health Center-based (JPHC) prospective study

BackgroundB vitamins and methionine are essential substrates in the one-carbon metabolism pathway involved in DNA synthesis and methylation. They may have essential roles in cancer development. We aimed to evaluate the associations of dietary intakes of vitamin B12, vitamin B6, folate, and methionine with the risk of esophageal cancer (EC) using data from the Japan Public Health Center-based Prospective Study.MethodsWe included 87,053 Japanese individuals who completed a food frequency questionnaire and were followed up from 1995–1998 to 2013 and 2015. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated by Cox proportional-hazard regression across quintiles of dietary intakes of B vitamins and methionine.ResultsAfter 1,456,678 person-years of follow-up, 427 EC cases were documented. The multivariable HR (95% CI) of incident EC in the highest versus lowest quintile of dietary intake of vitamin B12 was 1.75 (1.13–2.71; p-trend=0.01). Stratification analysis based on alcohol consumption showed that higher dietary intakes of vitamin B12 and methionine were associated with an increased risk of EC among never-drinkers; HRs (95% CIs) were 2.82 (1.18–6.74; p-trend=0.009; p-interaction=0.18) and 3.45 (1.32–9.06; p-trend=0.003; p-interaction 0.02) for vitamin B12 and methionine, respectively. Meanwhile, there was no association between vitamin B12 and methionine intake with the risk of EC among drinkers. There were no associations between dietary intake of folate or vitamin B6 and the risk of EC.ConclusionDietary intake of vitamin B12 was positively associated with the risk of EC in the Japanese population.

Dietary glycemic index, glycemic load, and endometrial cancer risk: The Japan Public Health Center-based Prospective Study.

Evidence supporting the association of glycemic index (GI) and glycemic load (GL) with the risk of endometrial cancer is controversial and reports from Asia were limited. Therefore, we aimed to investigate the association in Japanese women. We evaluated 52 460 women in the Japan Public Health Center‐based Prospective Study aged 45‐74 years who responded to the 5‐year follow‐up survey. GI and GL were calculated from a validated food frequency questionnaire, and the participants were divided into three groups by GI and GL. The hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated with the Cox proportional hazard model adjusted for potential confounding factors. As a result, within 15.5 years of follow‐up, 166 new cases of endometrial cancer were identified. Compared with the lowest GI and GL tertile groups, the HR of the risk of endometrial cancer in the highest GI tertile group was 0.80 (95% CI, 0.53‐1.20; Ptrend = .33), and that of the highest GL tertile group was 0.79 (95% CI, 0.52‐1.19; Ptrend = .82). The results were unchanged after stratification by body mass index, coffee consumption, and history of diabetes. In conclusion, we did not find any significant association between GI and GL with the risk of endometrial cancer. Further research is required to clarify the association.

Association of serum levels of antibodies against ALDOA and FH4 with transient ischemic attack and cerebral infarction

BackgroundIschemic stroke, including transient ischemic attack (TIA) and acute-phase cerebral infarction (aCI), is a serious health problem in the aging society. Thus, this study aimed to identify TIA and aCI biomarkers.MethodsIn 19 patients with TIA, candidate antigens recognized by serum IgG autoantibodies were screened using a human aortic endothelial cell cDNA library. Through amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA), serum antibody levels against the candidate antigens were examined in healthy donor (HD), TIA, and aCI cohorts (n = 285, 92, and 529). The plasma antibody levels in the Japan Public Health Center-based Prospective Cohort Study (1991–1993) were also examined.ResultsThe candidate antigens were aldolase A (ALDOA) and fumarate hydratase (FH). In AlphaLISA, patients with TIA or aCI had higher anti-ALDOA antibody (ALDOA-Ab) and anti-FH antibody (FH-Ab) levels than the HDs (P < 0.05). In a multivariate logistic regression analysis, the ALDOA-Ab (odds ratio [OR]: 2.46, P = 0.0050) and FH-Ab (OR: 2.49, P = 0.0037) levels were independent predictors of TIA. According to the case–control study, the ALDOA-Ab (OR: 2.50, P < 0.01) and FH-Ab (OR: 2.60, P < 0.01) levels were associated with aCI risk. In a correlation analysis, both ALDOA-Abs and FH-Abs were well associated with hypertension, coronary heart disease, and habitual smoking. These antibody levels also correlated well with maximum intima–media thickness, which reflects atherosclerotic stenosis.ConclusionsALDOA-Abs and FH-Abs can be novel potential biomarkers for predicting atherosclerotic TIA and aCI.

Serum anti-AP3D1 antibodies are risk factors for acute ischemic stroke related with atherosclerosis

Atherosclerosis has been considered as the main cause of morbidity, mortality, and disability worldwide. The first screening for antigen markers was conducted using the serological identification of antigens by recombinant cDNA expression cloning, which has identified adaptor-related protein complex 3 subunit delta 1 (AP3D1) as an antigen recognized by serum IgG antibodies of patients with atherosclerosis. Serum antibody levels were examined using the amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) using a recombinant protein as an antigen. It was determined that the serum antibody levels against AP3D1 were higher in patients with acute ischemic stroke (AIS), transient ischemic attack, diabetes mellitus (DM), cardiovascular disease, chronic kidney disease (CKD), esophageal squamous cell carcinoma (ESCC), and colorectal carcinoma than those in the healthy donors. The area under the curve values of DM, nephrosclerosis type of CKD, and ESCC calculated using receiver operating characteristic curve analysis were higher than those of other diseases. Correlation analysis showed that the anti-AP3D1 antibody levels were highly associated with maximum intima-media thickness, which indicates that this marker reflected the development of atherosclerosis. The results of the Japan Public Health Center-based Prospective Study indicated that this antibody marker is deemed useful as risk factors for AIS.

Dietary glycemic index, glycemic load and mortality: Japan Public Health Center-based prospective study.

Long-term associations of dietary glycemic index (GI) and glycemic load (GL) with mortality outcomes remain unclear. The present analysis included 72,783 participants of the Japan Public Health Center-based Prospective Study. Participants who responded to the 5-year follow-up questionnaire in 1995-1999 were followed-up until December 2015. We estimated the risk of total and cause-specific mortality associated with GI and GL using Cox proportional hazards regression models. During 1,244,553 person years of follow-up, 7535 men and 4913 women died. GI was positively associated with all-cause mortality. As compared with the lowest quartile, the multivariable HR for those who had the highest quartile of GI was 1.14 (95% CI 1.08-1.20). The HRs for death comparing the highest with the lowest quartile were 1.28 (95% CI 1.14-1.42) for circulatory system diseases, 1.33 (95% CI 1.14-1.55) for heart disease, 1.32 (95% CI 1.11-1.57) for cerebrovascular disease, and 1.45 (95% CI 1.18-1.78) for respiratory diseases. GI was not associated with mortality risks of cancer and digestive diseases. GL showed a null association with all-cause mortality (highest vs lowest quartile; HR 1.04; 95% CI 0.96-1.12). However, among those who had the highest quartile of GL, the HRs for death from circulatory system diseases was 1.24 (95% CI 1.05-1.46), cerebrovascular disease was 1.34 (95% CI 1.03-1.74), and respiratory diseases was 1.35 (95% CI 1.00-1.82), as compared with the lowest quartile. In this large prospective cohort study, dietary GI and GL were associated with mortality risks.

Relationship between unhealthy sleep status and dry eye symptoms in a Japanese population: The JPHC-NEXT study

PurposeTo investigate whether and how unhealthy sleep habits (i.e., the frequency of difficulty falling or staying asleep, and the frequency of waking up tired) and the duration of sleep are related to the prevalence of dry eye disease (DED) in a general population. MethodsThis study included a total of 106,282 subjects aged 40–74 years who participated in a baseline survey of the Japan Public Health Center-based Prospective Study for the Next Generation. DED was defined as the presence of clinically diagnosed DED or severe symptoms. Multivariable-adjusted logistic regression models were used to assess the relationships of various components of sleep status with DED. ResultsHigher frequencies of having difficulty falling or staying asleep, and waking up tired were significantly related to increased DED in both sexes (Ptrend<0.001). Compared with those with 8 h/day of sleep, shorter sleepers had an increased prevalence of DED in both sexes, although DED was increased among men who slept ≥10 h/day. By comparing participants with the greatest vs. the least difficulty of falling asleep, the multivariable-adjusted odds ratios (95% confidence interval [CI]) were 2.23 (95% CI, 1.99–2.49) for men and 1.91 (95% CI, 1.76–2.07) for women. When analyzed separately, the magnitude of each relationship was stronger with severe DED symptoms than with clinically diagnosed DED. ConclusionsSleep deprivation and poor sleep quality were significantly related to DED in a Japanese population.

Association of sugary drink consumption with all-cause and cause-specific mortality: the Japan Public Health Center-based Prospective Study

BackgroundFew epidemiologic studies have assessed the associations of sugary drink consumption with mortality outcomes among Asian populations. MethodsThis study included 70,486 participants in the Japan Public Health Center-based Prospective Study at the age of 45–74 years in 1995–1999. A validated food frequency questionnaire was used to assess the consumption of sugary drinks. We estimated the risk of total and cause-specific mortality associated with sugary drink consumption using Cox proportional hazards regression model. ResultsMean follow-up was 17.1 years, during which 11,811 deaths were documented. Sugary drink consumption was associated with higher total mortality, with multivariate HR of 1.06 (95% CI 1.00–1.13) for quintile 3, 1.07 (95% CI 1.01–1.13) for quintile 4, and 1.15 (95% CI 1.09–1.22) for quintile 5, compared with quintile 1 (P < 0.001 for trend). Additionally, positive associations with cause-specific mortality were observed, including death from circulatory system diseases (quintile 5 vs quintile 1; HR, 1.23; 95% CI 1.09–1.38) and heart disease (quintile 5 vs quintile 1; HR, 1.35; 95% CI 1.14–1.60). ConclusionIn this large Japanese prospective study, sugary drink consumption was associated with all-cause and cause-specific mortality.

Reproductive Factors and Lung Cancer Risk among Never-Smoking Japanese Women with 21 Years of Follow-Up: A Cohort Study.

Previous studies have reported inconsistent associations between reproductive factors and lung cancer. We used data from the Japan Public Health Center-based Prospective Study, which included 400 incident lung cancer cases (305 adenocarcinoma) among 42,615 never-smoking women followed for a median of 21 years, to examine the associations of reproductive and hormonal factors with lung cancer by histological type using Cox proportional hazards models. Longer fertility span (≥36 years vs. ≤32 years) was associated with increased risk of lung adenocarcinoma (HR, 1.48; 95% CI, 1.07-2.06, P trend = 0.01) but not with all lung cancer or nonadenocarcinoma. Similarly, late age at menopause (≥ 50 years) was associated with increased adenocarcinoma risk (vs. ≤ 47 years, HR, 1.41; 95% CI, 1.01-1.96, P trend 0.04). Compared with premenopausal women, women with natural menopause (HR, 1.99; 95% CI, 1.02-3.88) or surgical menopause (HR, 2.75; 95% CI, 1.33-5.67) were at increased risk of adenocarcinoma. In contrast, breastfeeding was associated with reduced risk of nonadenocarcinoma (HR, 0.51; 95% CI, 0.28-0.92). No significant association with parity, age at first birth, exogenous hormone use, or length of menstrual cycle was detected. Reproductive factors may play a role in lung carcinogenesis. Future studies that include estrogen and progesterone biomarkers may help clarify the role of endogenous hormones in lung carcinogenesis. Fertility span and age at menopause may be useful variables in developing risk prediction models for lung adenocarcinoma among nonsmoking women.

Long-term antihypertensive drug use and risk of cancer: The Japan Public Health Center-based prospective study.

Antihypertensive drugs have been reported as both promotors and suppressors of cancers and this relationship has been known for several decades. We examined a large‐scale prospective cohort study in Japan to assess the relationship between long‐term antihypertensive drug use, for 10 y, and carcinogenesis. We divided participants into 4 categories according to the period of antihypertensive drug use, and calculated the hazard ratios (HRs), 95% confidence intervals (CIs), and P trends using the Cox proportional hazard model. In all cancers, there was a significant difference in the medication period and the adjusted HR, as well as a significant difference in the P trend. Furthermore, more than 10 y use of antihypertensive drugs significantly increased the adjusted HR in colorectal cancer (multivariable HR: 1.18, 95% CI: 1.01‐1.37 in the >10 y use group; P for trend = .033) and renal cancer (multivariable HR: 3.76, 95% CI: 2.32‐6.10 in the 5‐10 y use group; multivariable HR: 2.14, 95% CI: 1.29‐3.56 in the >10 y use group; P for trend < .001). The highest adjusted HR in renal cancer among antihypertensive drug users was observed in the analysis performed on patients in which the outcomes were calculated from 3 y after the 10‐y follow‐up survey and by sex. A large‐scale cohort study in Japan suggested that long‐term use of antihypertensive drugs may be associated with an increased incidence of colorectal and renal cancer.

Dietary Acrylamide Intake and the Risks of Renal Cell, Prostate, and Bladder Cancers: A Japan Public Health Center-Based Prospective Study.

Acrylamide can be carcinogenic to humans. However, the association between the acrylamide and the risks of renal cell, prostate, and bladder cancers in Asians has not been assessed. We aimed to investigate this association in the Japan Public Health Center-based Prospective Study data in 88,818 Japanese people (41,534 men and 47,284 women) who completed a food frequency questionnaire in the five-year follow-up survey in 1995 and 1998. A validated food frequency questionnaire was used to assess the dietary acrylamide intake. Cox proportional hazard regression models were used to estimate hazard ratios and 95% confidence intervals (CIs). During a mean follow-up of 15.5 years (15.2 years of prostate cancer), 208 renal cell cancers, 1195 prostate cancers, and 392 bladder cancers were diagnosed. Compared to the lowest quintile of acrylamide intake, the multivariate hazard ratios for the highest quintile were 0.71 (95% CI: 0.38–1.34, p for trend = 0.294), 0.96 (95% CI: 0.75–1.22, p for trend = 0.726), and 0.87 (95% CI: 0.59–1.29, p for trend = 0.491) for renal cell, prostate, and bladder cancers, respectively, in the multivariate-adjusted model. No significant associations were observed in the stratified analyses based on smoking. Dietary acrylamide intake was not associated with the risk of renal cell, prostate, and bladder cancers.

Plasma phospholipid n-3 polyunsaturated fatty acids and major depressive disorder in Japanese elderly: the Japan Public Health Center-based Prospective Study

The beneficial effects of n-3 polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on depression are not definitively known. In a previous population-based prospective cohort study, we found a reverse J-shaped association of intake of fish and docosapentaenoic acid (DPA), the intermediate metabolite of EPA and DHA, with major depressive disorder (MDD). To examine the association further in a cross-sectional manner, in the present study we analyzed the level of plasma phospholipid n-3 PUFAs and the risk of MDD in 1,213 participants aged 64–86 years (mean 72.9 years) who completed questionnaires and underwent medical check-ups, a mental health examination, and blood collection. In multivariate logistic regression analysis, odds ratios and 95% confidence intervals were calculated for MDD according to plasma phospholipid n-3 PUFA quartiles. MDD was diagnosed in 103 individuals. There were no significant differences in any n-3 PUFAs (i.e., EPA, DHA, or DPA) between individuals with and without MDD. Multivariate logistic regression analysis showed no significant association between any individual n-3 PUFAs and MDD risk. Overall, based on the results of this cross-sectional study, there appears to be no association of plasma phospholipid n-3 PUFAs with MDD risk in the elderly Japanese population.