Timely Topics, Nov 2008

1. NIGHTTIME EATING; COMMONLY OBSERVED AND RELATED TO WEIGHT GAIN IN AN INPATIENT FOOD INTAKE STUDY

Marci E Gluck, Colleen A Venti, Arline D Salbe and Jonathan Krakoff

¹From the Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ (MEG, CAV, and JK); and the Kronos Longevity Research Institute, Phoenix, AZ (ADS)

Background: Nighttime food intake has rarely been studied in inpatient settings and only one study observed a relation between self-reported nighttime eating and weight gain.

Objective: We investigated the prevalence of nighttime eating and its effect on weight change.

Design: Healthy nondiabetic Pima Indians (n = 117; 67 M, 50 F) and whites (n = 43; 29 M, 13 F) were admitted to a clinical research unit. After consuming a standardized diet for 3 d, participants ate ad libitum from a computer-operated vending machine that recorded the time of food selection. Energy intake was calculated as mean kcal/d. Follow-up weight was available for 94 volunteers.

Results: Fifty-five subjects (36%) were nighttime eaters (NEs; persons who ate between 2300 and 0500 on &ge 1 of the 3 d). Prevalence was similar among whites and Pima Indians (37% and 35%, respectively). There were no significant differences in body mass index or percentage body fat between NEs and non-NEs. NEs consumed more calories per day (4758) than did non-NEs (4244; P = 0.02), but the percentage of calories from macronutrients did not differ. NEs consumed &asymp 15% (690 kcal) of their daily energy during nighttime episodes. After control for baseline weight and follow-up time ( &x ± SD: 3.4 ± 1.8 y), NEs (n = 29) gained more weight (6.2 kg) than did non-NEs (n = 65; 1.7 kg; P = 0.03).

Conclusions: Nighttime eating was common, and it predicted weight gain. It remains to be determined whether this behavior indicates abnormal sleep patterns leading to nighttime wakefulness and food intake in those prone to weight gain.

Source: American Journal of Clinical Nutrition, Vol. 88, No. 4, 900-905, October 2008

2. COFFEE, TEA AND INCIDENT TYPE 2 DIABETES: THE SINGAPORE CHINESE HEALTH STUDY

Andrew O Odegaard, Mark A Pereira, Woon-Puay Koh, Kazuko Arakawa, Hin-Peng Lee and Mimi C Yu

¹From the Division of Epidemiology and Community Health (AOO and MAP), and the Cancer Center (KA and MCY), University of Minnesota, Minneapolis, MN, and the Department of Community, Occupational, and Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (W-PK and H-PL)

Background: Increasing coffee intake was inversely associated with risk of type 2 diabetes in populations of European descent; however, data from high-risk Asian populations are lacking as are data on tea intake in general.

Objective: We investigated the prospective associations between intakes of coffee, black tea, and green tea with the risk of type 2 diabetes in Singaporean Chinese men and women.

Design: We analyzed data from 36 908 female and male participants in the Singapore Chinese Health Study aged 45–74 y in 1993–1998 who had multiple diet and lifestyle measures assessed and then were followed up between 1999 and 2004. We used Cox regression models to investigate the association of baseline coffee and tea intakes with incident type 2 diabetes during follow-up, with adjustment for a number of possible confounding or mediating variables.

Results: In multivariate models participants reporting ≥ 4 cups of coffee/d had a 30% reduction in risk of diabetes [relative risk (RR): 0.70; 95% CI: 0.53, 0.93] compared with participants who reported non daily consumption. Participants reporting ≥ 4 cup of black tea/d had a suggestive 14% reduction in risk of diabetes (RR: 0.86; 95% CI: 0.74, 1.00) compared with participants who reported 0 cups/d, and we observed no association with green tea.

Conclusion: Regular consumption of coffee and potentially black tea, but not green tea, is associated with lower risk of type 2 diabetes in Asian men and women in Singapore.

3. CULTURED MILK, YOGURT, AND DAIRY INTAKE IN RELATION TO BLADDER CANCER RISK IN A PROSPECTIVE STUDY OF SWEDISH WOMEN AND MEN

Susanna C Larsson¹,Swen-Olof Andersson¹,Jan-Erik Johansson¹ and Alicja Wolk¹

¹ From the Division of Nutritional Epidemiology, National Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden (SCL and AW), and the Department of Urology and Center for Assessment of Medical Technology, Örebro University Hospital, Örebro, Sweden (S-OA and J-EJ)

Background:Findings from epidemiologic studies of the effect of dairy foods (mainly milk) on the risk of bladder cancer have been inconsistent.

Objective:We aimed to examine the association between the intake of cultured milk and other dairy foods and the incidence of bladder cancer in a prospective, population-based cohort.

Design:We prospectively followed 82 002 Swedish women and men who were cancer-free and who completed a 96-item food-frequency questionnaire in 1997. Incident cases of bladder cancer were identified in the Swedish cancer registries.

Results:During a mean follow-up of 9.4 y, 485 participants (76 women and 409 men) were diagnosed with bladder cancer. Total dairy intake was not significantly associated with risk of bladder cancer [&ge 7.0 servings/d compared with < 3.5 servings/d: multivariate rate ratio (RR) = 0.87; 95% CI: 0.66, 1.15; P for trend = 0.33]. However, a statistically significant inverse association was observed for the intake of cultured milk (sour milk and yogurt). The multivariate RRs for the highest category of cultured milk intake (&ge 2 servings/d) compared with the lowest category (0 serving/d) were 0.62 (95% CI: 0.46, 0.85; P for trend = 0.006) in women and men combined, 0.55 (95% CI: 0.25, 1.22; P for trend = 0.06) in women, and 0.64 (95% CI: 0.46, 0.89; P for trend = 0.03) in men. The intake of milk or cheese was not associated with bladder cancer risk.

Conclusion: These findings suggest that a high intake of cultured milk may lower the risk of developing bladder cancer.

4) THE ASSOCIATION OF GLYCEMIC LOAD AND CARBOHYDRATE INTAKE WITH COLORECTAL CANCER RISK IN THE MULTIETHNIC COHORT STUDY

Nancy C Howarth¹,Suzanne P Murphy¹,Lynne R Wilkens¹,Brian E Henderson¹ and Laurence N Kolonel¹

¹From the Cancer Epidemiology Program, Cancer Research Center of Hawai‘i, University of Hawai‘i, Honolulu, HI (NCH, SPM, LRW, and LNK), and the University of Southern California, Los Angeles, CA (BEH)

Background: High glycemic-load diets may increase colorectal cancer risk through hyperinsulinemic effects.

Objective:We analyzed data for 191 004 participants in the Multiethnic Cohort Study to determine the risk of colorectal cancer associated with glycemic load (GL), carbohydrate, and sucrose and to ascertain whether this risk was modified by sex and ethnicity.

Design: During 8 y of follow-up, 2379 incident cases of colorectal adenocarcinoma occurred. We used baseline quantitative food-frequency questionnaire data to assess usual dietary intake over the preceding year. Using Cox regression, we calculated adjusted relative risks (RRs) and 95% CIs for colorectal cancer associated with quintiles of GL, carbohydrate, and sucrose.

Results: For both men and women in this cohort, white rice was the major contributor to GL. In multivariate models, RRs for colorectal cancer decreased significantly with increasing GL in women (RR for the highest quintile versus the lowest: 0.75; 95% CI: 0.57, 0.97; P for trend = 0.02) but not in men (RR: 1.15; 95% CI: 0.89, 1.48; P for trend = 0.19). Results for carbohydrate and sucrose were similar. The inverse association with GL was found in women of all ethnic groups (P for interaction = 0.58). In men, an interaction was found between ethnicity and GL (P < 0.01): white men had a positive association with increasing GL (RR: 1.69; 95% CI: 0.98, 2.92; P for trend < 0.01), but men of other ethnic groups did not.

Conclusion: GL and carbohydrate intake appear to protect against colorectal cancer in women in the Multiethnic Cohort, perhaps because a major source of GL is white rice.

Source: American Journal of Clinical Nutrition, Vol. 88, No. 4, 1074-1082, October 2008

5. EFFECT OF MODETATE ALCOHOL CONSUMPTION ON LIVER ENZYMES INCREASES WITH INCREASING BODY MASS INDEX

Päivikki I Alatalo¹,Heidi M Koivisto¹,Johanna P Hietala¹,Katri S Puukka¹,Risto Bloigu¹and Onni J Niemelä¹

¹From the Department of Laboratory Medicine and Medical Research Unit, Seinäjoki Central Hospital and University of Tampere, Seinäjoki, Finland (PIA, HMK, JPH, KSP, and OJN), and the Medical Informatics Group, University of Oulu, Finland (RB)

Background: Although both ethanol consumption and overweight alter the activities of hepatic enzymes in circulation, the differentiation of an alcohol or non alcohol basis for such changes remains problematic. The magnitude of alterations occurring among moderate drinkers has remained obscure.

Objective: We examined the links between moderate ethanol consumption, body mass index (BMI; in kg/m2), and liver enzymes.

Design: Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST),  and &gamma -glutamyltransferase (GGT) were recorded from 2164 apparently healthy participants (1028 men, 1136 women) reporting either no alcohol (abstainers) or <40 g ethanol consumption per day (moderate drinkers). The study population was further classified according to BMI as follows: <19 (underweight), &ge 19 and <25 (normal weight), &ge 25 and <30 (overweight), and &ge 30 (obese).

Results: Serum ALT (P < 0.05) and GGT (P < 0.001) but not AST (P = 0.805) activities in moderate drinkers were higher than those in abstainers. For all enzymes, a significant main effect was observed of increasing BMI, which was more striking in moderate drinkers than in abstainers. Tests of between-subjects effects indicated significant interactions with sex and drinking status, although not with sex and BMI.

Conclusions: The effect of moderate alcohol consumption on liver enzymes increases with increasing BMI. These findings should be considered in the clinical assessment of overweight alcohol consumers and in the definition of normal ranges for liver enzymes. These results may also help to develop new approaches for examining patients with fatty liver induced by either ethanol or adiposity.

6. DIETARY GLYCEMIC INDEX AND THE RISK OF AGE-RELATED MACULAR DEGENERATION

Shweta Kaushik, Jie Jin Wang, Victoria Flood, Jennifer Sue Ling Tan, Alan W Barclay, Tien Y Wong, Jennie Brand-Miller and Paul Mitchell

¹From the Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute, University of Sydney, Sydney, Australia (SK, JJW, VF, JSLT, and PM); the Centre for Eye Research Australia, University of Melbourne, Australia (JJW and TYW); the Human Nutrition Unit, Department of Molecular and Microbial Biosciences, University of Sydney, Sydney, Australia (VF, AWB, and JB-M); and the Department of Ophthalmology, National University of Singapore, Singapore, Republic of Singapore (TYW)

Background: Dietary factors are known risk factors for age-related macular degeneration (AMD)—the leading cause of visual loss among persons aged &ge65 y. High-glycemic-index diets have been hypothesized as a risk factor for AMD, but prospective data are unavailable.

Objective: The objective was to examine the association between dietary glycemic index and the 10-y incidence of AMD in the Blue Mountain Eye Study population.

Design: This was a population-based cohort study with 3654 participants &ge 49 y) examined at baseline (1992–1994); 2335 patients were reexamined after 5 y and 1952 after 10 y. The Wisconsin System was used to grade 10-y incident early and late AMD from retinal photographs. A food-frequency questionnaire was used to collect dietary information at baseline, and an Australian database was used to calculate the mean glycemic index.

Results: Over 10 y, 208 of 1810 persons (cumulative incidence: 14.1%) developed early AMD. After age, smoking, other risk factors, and dietary constituents were adjusted for, a higher mean dietary glycemic index was associated with an increased 10-y risk of early AMD in a comparison of quartiles 1 and 4 [relative risk (RR): 1.77; 95% CI: 1.13, 2.78; P for trend = 0.03]. Conversely, a greater consumption of cereal fiber (RR: 0.68; 95% CI: 0.44, 1.04; P for trend = 0.05) and breads and cereals (predominantly lower glycemic index foods such as oatmeal) (RR: 0.67; 95% CI: 0.44, 1.02; P for trend = 0.03) was associated with a reduced risk of incident early AMD. No relation was observed with late AMD.

Conclusions: A high-glycemic-index diet is a risk factor for early AMD—the recognized precursor of sight-threatening late AMD. Low-glycemic-index foods such as oatmeal may protect against early AMD.
Source: American Journal of Clinical Nutrition, Vol. 88, No. 4, 1104-1110, October 2008