Scientists Believe They Found Why Obesity Is Linked To Prostate Cancer Deaths

A Study entitled “Prediagnostic Body-Mass Index, Plasma C-Peptide Concentration, and Prostate Cancer—Specific Mortality In Men With Prostate Cancer: A Long-Term Survival Analysis.”

Done by:

Ma J, Li H, Giovannucci E, Mucci L, Qiu W, Nguyen PL, Gaziano JM, Pollak M, Stampfer MJ.

Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA.

And soon to be published in the British Medical Journal “Lancet”

According to the study which involved men diagnosed with prostate cancer during the 24 years of follow-up in the Physicians‘ Health Study…

BMI measurements were available at baseline in 1982 and eight years later in 1990 for 2546 men who developed prostate cancer.

Baseline C-peptide concentration was available in 827 men. We used Cox proportional hazards regression models controlling for age, smoking, time between BMI measurement and prostate cancer diagnosis, and competing causes of death to assess the risk of prostate cancer-specific mortality according to BMI and C-peptide concentration.

Crucial Information…

Of the 2546 men diagnosed with prostate cancer during the follow-up period, 989 (38.8%) were overweight (BMI 25.0-29.9 kg/m(2)) and 87 (3.4%) were obese (BMI >/=30 kg/m(2)).

281 men (11%) died from prostate cancer during this follow-up period.

Compared with men of a healthy weight (BMI <25 kg/m(2)) at baseline, overweight men and obese men had a significantly higher risk of prostate cancer mortality (proportional hazard ratio [HR] 1.47 [95% CI 1.16-1.88] for overweight men and 2.66 [1.62-4.39] for obese men; p(trend)<0.0001).

The trend remained significant after controlling for clinical stage and Gleason grade and was stronger for prostate cancer diagnosed during the PSA screening era (1991-2007) compared with during the pre-PSA screening era (1982-1990) or when using BMI measurements obtained in 1990 compared with those obtained in 1982. Of the 827 men with data available for baseline C-peptide concentration, 117 (14%) died from prostate cancer.

Men with C-peptide concentrations in the highest quartile (high) versus the lowest quartile (low) had a higher risk of prostate cancer mortality (HR 2.38 [95% CI 1.31-4.30]; p(trend)=0.008). Compared with men with a BMI less than 25 kg/m(2) and low C-peptide concentrations, those with a BMI of 25 kg/m(2) or more and high C-peptide concentrations had a four-times higher risk of mortality (4.12 [1.97-8.61]; p(interaction)=0.001) independent of clinical predictors.

Interpretation:

Excess bodyweight and a high plasma concentration of C-peptide both predispose men with a subsequent diagnosis of prostate cancer to an increased likelihood of dying of their disease. Patients with both factors have the worst outcome. Further studies are now needed to confirm these findings.

A Second Study…

Insulin-Like Growth Factors, Their Binding Proteins, And Prostate Cancer Risk: Analysis Of Individual Patient Data From 12 Prospective Studies.

Done By:

Roddam AW, Allen NE, Appleby P, Key TJ, Ferrucci L, Carter HB, Metter EJ, Chen C, Weiss NS, Fitzpatrick A, Hsing AW, Lacey JV Jr, Helzlsouer K, Rinaldi S, Riboli E, Kaaks R, Janssen JA, Wildhagen MF, Schröder FH, Platz EA, Pollak M, Giovannucci E, Schaefer C, Quesenberry CP Jr, Vogelman JH, Severi G, English DR, Giles GG, Stattin P, Hallmans G, Johansson M, Chan JM, Gann P, Oliver SE, Holly JM, Donovan J, Meyer F, Bairati I, Galan P.

Cancer Epidemiology Unit, University of Oxford, Richard Doll Building, Roosevelt Drive, Oxford OX3 7LF, United Kingdom.

Background for the Study

Some, but not all, published results have shown an association between circulating blood levels of some insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) and the subsequent risk for prostate cancer.

Purpose of the Study

To assess the association between levels of IGFs and IGFBPs and the subsequent risk for prostate cancer.

Data Sources

Studies identified in PubMed, Web of Science, and CancerLit.

Study Selection

The principal investigators of all studies that published data on circulating concentrations of sex steroids, IGFs, or IGFBPs and prostate cancer risk using prospectively collected blood samples were invited to collaborate.

Data Extraction

Investigators provided individual participant data on circulating concentrations of IGF-I, IGF-II, IGFBP-II, and IGFBP-III and participant characteristics to a central data set in Oxford, United Kingdom.

Data Synthesis

The study included data on 3700 men with prostate cancer and 5200 control participants.

On average, case patients were 61.5 years of age at blood collection and received a diagnosis of prostate cancer 5 years after blood collection.

The greater the serum IGF-I concentration, the greater the subsequent risk for prostate cancer (odds ratio [OR] in the highest vs. lowest quintile, 1.38 [95% CI, 1.19 to 1.60]; P < 0.001 for trend).

Neither IGF-II nor IGFBP-II concentrations were associated with prostate cancer risk, but statistical power was limited.

Insulin-like growth factor I and IGFBP-III were correlated (r = 0.58), and although IGFBP-III concentration seemed to be associated with prostate cancer risk, this was secondary to its association with IGF-I levels.

Insulin-like growth factor I concentrations seemed to be more positively associated with low-grade than high-grade disease; otherwise, the association between IGFs and IGFBPs and prostate cancer risk had no statistically significant heterogeneity related to stage or grade of disease, time between blood collection and diagnosis, age and year of diagnosis, prostate-specific antigen level at recruitment, body mass index, smoking, or alcohol intake.

Limitations

Insulin-like growth factor concentrations were measured in only 1 sample for each participant, and the laboratory methods to measure IGFs differed in each study. Not all patients had disease stage or grade information, and the diagnosis of prostate cancer may differ among the studies.

Conclusion

High circulating IGF-I (Insulin) concentrations are associated with a moderately increased risk for prostate cancer.

One Last Study regarding Insulin and Enlarged Prostate (BPH)

Insulin and Free Oestradiol Are Independent Risk Factors For Benign Prostatic Hyperplasia.

Hammarsten J, Damber JE, Karlsson M, Knutson T, Ljunggren O, Ohlsson C, Peeker R, Smith U, Mellström D.

Department of Urology, Skaraborg Hospital, Skövde, Sweden.

The aetiology of benign prostatic hyperplasia (BPH) remains unclear.

The objective of the present study was to test the insulin, oestradiol and metabolic syndrome hypotheses as promoters of BPH.

The design was a risk factor analysis of BPH in which the total prostate gland volume was related to endocrine and anthropometric factors.

The participants studied were 184 representative men, aged 72-76 years, residing in Göteborg, Sweden.

Using a multivariate analysis, BPH as measured by the total prostate gland volume correlated statistically significantly with fasting serum insulin (beta=0.200, P=0.028), free oestradiol (beta=0.233, P=0.008) and lean body mass (beta=0.257, P=0.034).

Insulin and free oestradiol appear to be independent risk factors for BPH, confirming both the insulin and the oestradiol hypotheses. Our findings also seem to confirm the metabolic syndrome hypothesis. The metabolic syndrome and its major endocrine aberration, hyperinsulinaemia, are possible primary events in BPH.

Take Aways From These Studies…

Get your weight to a healthy level. This will help you control insulin in your body. When you control insulin by maintaining a healthy weight — notice I did not say “Normal” because normal is based on the average of men today,and the average weights have gone up to above healthy.

So you can see how your keeping a healthy weight can help you avoid developing porstate cancer.

Maintaining a healthy weight is only one of the weapons at your disposal to fight off prostate cancer. Other arrows in your quiver include, avoiding certain foods; eating certain foods; regularly taking a supplement based on scientifically proven ingredients (like Smarter Prostate Formula™ which we developed); getting screened regularly.

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Posted under Enlarged Prostate (BPH), Prostate Cancer